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Balbharti Maharashtra State Board Class 7 Civics Solutions Chapter 4 Fundamental Rights Part 1 Notes, Textbook Exercise Important Questions and Answers.

Maharashtra Board Class 7 Civics Solutions Chapter 4 Fundamental Rights Part 1

Class 7 Civics Chapter 4 Fundamental Rights Part 1 Textbook Questions and Answers

1. Answer the following questions in brief:

Question 1.
What do you understand by ‘Fundamental Rights’?
Answer:
(i) Demanding one’s rights is insisting on creating an atmosphere conducive to the development of the self as well as the entire society.

(ii) The Indian Constitution has guaranteed equal rights to all citizens in order to create this conducive atmosphere.

(iii) These rights are Fundamental Rights.

Question 2.
Name the awards that are conferred by the Government upon people for their distinguished contribution in different fields.
Answer:
Padmashree, Padmabhushan, Padmavibhushan.

Question 3.
Why is it prohibited to employ children under 14 years of age in hazardous places?
Answer:
(i) Employing children under 14 years of age in hazardous places can be dangerous. Children may be grievously injured and they may even lose their life.

(ii) To prevent the exploitation of children and ban oppression of any kind, it is prohibited to employ children under 14 years of age in hazardous places.

Question 4.
Why has the Constitution given equal rights to all citizens?
Answer:
(i) We get rights at birth. Every newborn baby has a right to live.

(ii) The entire society and government takes efforts to ensure that the baby is in the best of health.

(iii) Only when all individuals get protection from injustice, exploitation, discrimination and deprivation, will they be able to develop their skills and qualities.

(iv) Demanding one’s rights is insisting on creating an atmosphere conducive to the development of the self as well as the entire society.

(v) The Indian Constitution has guaranteed equal rights to all citizens in order to create this conducive atmosphere.

2. Prepare a picture strip on the right to liberty
Answer:

3. Correct and rewrite the following sentences:

Question 1.
No one gets rights at birth.
Answer:
We get rights at birth.

Question 2.
Government can deprive you of a job by discriminating on the basis of religion, sex, place of birth while giving government jobs.
Answer:
According to the Right to Equality mentioned in our Constitution the State cannot discriminate against any citizen on grounds of religion, sex, place of birth or other grounds

4. Complete the following graphical description.

Answer:

Activities:

• Collect news clippings about certain important rights like the right to information, right to education, etc.
• If you find small children working on construction sites in your neighbourhood, talk to them and their parents about their problems and present the problems in your class.

Class 7 Civics Chapter 4 Fundamental Rights Part 1 InText Questions and Answers

Do this:

Following are the actions of A, B and C. Which kind of freedom do you connect them with?

Question 1.
‘A’ established ‘Adivasi Co-operation Forum’ to solve the problems of the tribal people.
Answer:
Freedom to Assemble Peacefully.

Question 2.
‘B’ decided to move his father’s bakery production from Goa to Maharashtra.
Answer:
Freedom to move freely throughout the territory of India.

Question 3.
‘C’ found some lacunae in the new tax policy of the Government. He wrote an artide about it and sent it to a newspaper for publication.
Answer:
Freedom of Speech and Expression.

Let’s discuss:

Question 1.

• Children are not employed here.
• Workers are paid daily here.

You see such boards in shops and hotels. In what way are they related to the Fundamental rights in the Constitution?
Answer:
They ensure that the Right against Exploitation mentioned in the Constitution is honoured and the right is not denied to the workers and children.

Question 2.
You must be aware of children’s rights. Can you name two important rights of children?
Answer:
(a) Right to Protection:

• Right to be protected from all sorts of violence.
• Right to be protected from physicaL and sexual abuse.
• Right to be protected from dangerous drugs.

(b) Right to Development

• Right to education
• Right to learn
• Right to relax and play
• Right to all forms of development – emotional, mental and physical.

Question 3.
Can rights be taken away?
Answer:
No, the rights cannot be taken away by anyone.

Question 4.
If rights are taken away, who should we contact for redressal?
Answer:
If rights are taken away one may appeal in the courts to seek justice for the same.

Question 5.
If the pet animals could speak, what rights do you think they would ask from you?
Answer:

• The right to roam around freely, wherever and whenever they wish.
• Right to expression
• Right to eat whatever they want whenever they want.

Question 6.
What are the advantages of equality before law and equal protection of the law?
Answer:

• There is no discrimination among citizens as superior – inferior, as men-women or while extending any protections like protection from arrest without a warrant.
• There is no discrimination among the citizens on the basis of religion, caste, race, sex, place of birth or residence.
• The inhuman practice of untouchability has been abolished in order to establish equality in the Indian society.
• Titles like Raja, Maharaja, Raobahadur etc. have also been abolished.

Class 7 Civics Chapter 4 Fundamental Rights Part 1 Additional Important Questions and Answers

Complete the sentence by choosing the appropriate words from the options given below:

Question 1.
The ______ has guaranteed equal rights to all citizens in order to create a conducive atmosphere.(Indian judiciary, Indian Government, Indian Constitution)
Answer:
Indian Constitution

Question 2.
We have protection from arrest without _______. (prior intimation, proof, warrant)
Answer:
warrant

Question 3.
________ gives a guarantee of all the liberties necessary from the point of view of an individual. (Right to Equality, Right to Liberty Right against Exploitation)
Answer:
Right to Liberty

Question 4.
______ implies getting a guarantee to live and availability of a conducive environment for living. (Right against Exploitation, Right to
Liberty, Right to Life)
Answer:
Right to Life

Question 5.
All children between 6 and ______ years of age are entitled to get education as a Fundamental Right. (11,10,14)
Answer:
14

Question 6.
It is prohibited to employ children under _______ years of age in hazardous places. (10,14,16)
Answer:
16

Match the following:

Question 1.

Column ‘A’	Column ‘B’
(1) Right to Equality	(a) liberties necessary from the point of view of individuals
(2) Right to Liberty	(b) bans all types of oppression.
(3) Right against	(c) No discrimination
Exploitation	amongst citizens.

Answer:
1 – c
2 – a
3 – b

Name the following:

Question 1.
The equal rights guaranteed to all citizens by the Indian Constitution in order to create a conducive atmosphere for the development of the self and the entire society.
Answer:
Fundamental Rights.

Question 2.
According to this right, the State cannot discriminate among citizens as superior- interior or men-women and cannot give different treatment or privileges to anybody.
Answer:
Right to Equality.

Question 3.
The State cannot discriminate against any citizen on these grounds for government employment.
Answer:
Religion, caste, race, sex, descent or place of birth or religion.

Question 4.
This inhuman practice that was prevalent in our country has been abolished by law.
Answer:
Untouchability.

Question 5.
These titles have been abolished as it creates artificial hierarchy among people.
Answer:
Raja, Maharaja, Raobahadur.

Question 6.
Any two freedoms we enjoy as Indian citizens.
Answer:
Freedom of Speech and Expression, Freedom to Assemble Peacefully.

Question 7.
The new right included in the Right to Liberty.
Answer:
Right to Education.

Question 8.
Children between this age group are entitled to get education as a Fundamental Right.
Answer:
6-14 years.

Question 9.
Two places where children cannot be made to work.
Answer:
Factories, Mines.

Question 10.
It implies getting a guarantee to live and availability of a conducive environment for living.
Answer:
Right to Life.

Answer in one or two sentences:

Question 1.
When will individual be able to develop their skills and qualities?
Answer:
Only when all individuals get protection from injustice, exploitation, discrimination and deprivation, will the individuals be able to j develop their skills and qualities.

Question 2.
What does demanding one’s rights imply?
Answer:
Demanding one’s rights is insisting on creating an atmosphere conducive to the development of the self as well as the entire society.

Question 3.
What does the Right to Education ensure?
Answer: Right to Education ensures that no child between the age of 6 and 14 will be deprived of education.

Question 4.
Which are the different forms of exploitation which are prevented through Right against Exploitation?
Answer:
Bonded labour or forcing somebody to work against his wish, treating somebody like a slave, denying them legitimate compensation, making them do excessive or strenuous work, starving them or ill-treating them are different forms of exploitation which are prevented through Right against Exploitation

Write short notes on:

Question 1.
Right to Equality
Answer:
According to the Right to Equality, the State cannot discriminate among citizens as superior-inferior or a men-women and cannot give different treatment or privileges to anybody. The same law applies equally to all. Many laws give protection. For example, we have protection from arrest without warrant. The State cannot discriminate even while extending such protection.

Question 2.
Right to Liberty
Answer:
This is a very important right given by the Constitution. It gives a guarantee of all the liberties necessary from the point of view of the individual. As Indian citizens, we have the right to:

• Freedom of speech and expression.
• Freedom to assemble peacefully.
• Freedom to form associations or unions.
• Freedom to move freely throughout the territory of India.
• Freedom to reside and settle in any part of the territory of India.
• Freedom to practise any profession, or to carry on any occupation, trade or business.

Question 3.
Right against Exploitation
Answer:
(i) The right against exploitation implies the right to prevent exploitation.

(ii) While the Constitution has banned all types of oppressions through the right against exploitation, it has made a special provision to prevent the exploitation of children.

(iii) Accordingly, it is prohibited to employ children under 14 years of age in hazardous places.

(iv) Children cannot be employed or made to work in factories and mines.

(v) Exploitation includes bonded labour or forcing somebody to work against his wish, treating somebody like a slave, denying them legitimate compensation, making them do excessive or strenuous work, starving them or ill-treating them.

(vi) Generally women, children, the weaker sections of society and powerless people are exploited.

(vii) This right enables us to stand up against any kind of exploitation.

Correct and rewrite the following sentences:

Question 1.
No one gets rights at birth.
Answer:
We get rights at birth.

Question 2.
The government can deprive you of a job by discriminating on the basis of religion, sex, place of birth while giving government jobs.
Answer:
According to the Right to Equality mentioned in our Constitution the State cannot discriminate against any citizen on grounds of religion, sex, place of birth or other grounds.

Question 3.
People can have titles like Raja, Maharaja, Raobahadur etc.
Answer:
The Constitution has abolished titles like Raja,, Maharaja, Raobahadur etc., that create aq artificial hierarchy among people.

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 14 Measurement and Effects of Heat Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 8 Science Solutions Chapter 14 Measurement and Effects of Heat

Class 8 Science Chapter 14 Measurement and Effects of Heat Textbook Questions and Answers

1. A. Whom should I pair with?

Question a.

Group ‘A’	Group ‘B’
1. Temperature of a healthy human body	a. 296 K
2. Boiling point of water	b. 98.6 °F
3. Room temperature	c. 0°C
4. Freezing point of water	d. 212 °F

Answer:

Group ‘A’	Group ‘B’
1. Temperature of a healthy human body	b. 98.6 °F
2. Boiling point of water	d. 212 °F
3. Room temperature	a. 296 K
4. Freezing point of water	c. 0°C

B. Who is telling the truth?

Question a.
The temperature of a substance is measured in joule.
Answer:
False. (The temperature of a substance is measured in °C or °F or K.)

Question b.
Heat flows from an object at higher temperature to an object at lower temperature.
Answer:
True.

Question c.
The joule is the unit of heat.
Answer:
True.

Question d.
Objects contract on heating.
Answer:
False. (In general, objects expand on heating. There are some exceptions to this, you will learn about them in Standard X.)

Question e.
Atoms of a solid are free.
Answer:
False. (Atoms of a solid are bound to each other due to the forces acting between them.)

Question f.
The average kinetic energy of atoms in a hot object is less than the average kinetic energy of atoms in a cold object.
Answer:
False. (The average kinetic energy of atoms in a hot object is more than the average kinetic energy of atoms in a cold object.)

C. You will find if you search.

Question a.
A thermometer is used to measure ……………. .
Answer:
A thermometer is used to measure temperature.

Question b.
The apparatus used to measure heat is called a ………… .
Answer:
The apparatus used to measure heat is called a calorimeter.

Question c.
Temperature is the measure of the …………. kinetic energy of the atoms in a substance.
Answer:
Temperature is the measure of the average kinetic energy of the atoms in a substance.

Question d.
The heat contained in a substance is the measure of the ………….. kinetic energy of the atoms in the substance.
Answer:
The heat contained in a substance is the measure of the total kinetic energy of the atoms in the substance.

2. Nishigandha kept a vessel containing all the ingredients for making tea in a solar cooker. Shivani kept a similar vessel on a stove. Whose tea will be ready first and why?

Question a.
Nishigandha kept a vessel containing all the ingredients for making tea in a solar cooker. Shivani kept a similar vessel on a stove. Whose tea will be ready first and why?
Answer:
Shivani’s tea will be ready first.
Reason: In a given time, the amount of heat received by the vessel on a stove is far greater than that received by the vessel kept in a solar cooker.

3. Write brief answers.

Question a.
Describe a clinical thermometer. How does it differ from the thermometer used in a laboratory?
Answer:
A clinical thermometer has a narrow stem and a long bulb filled with mercury (or alcohol). There is a small constriction in the stem above the bulb. When the bulb of the thermometer is held in the armpit or the mouth of a patient, the mercury (or alcohol) in the bulb rises in the stem.

When it is taken out of the patient’s body, the small constriction does not allow the mercury (or alcohol) from the stem to retreat into the bulb. Thus, this arrangement enables us to read the temperature of the patient’s body at ease after the removal of the thermometer from his body.

The clinical thermometer is graduated from 35 °C to 42 °C (or from 95 °F to 108 °F). At 37 °C (98.6 °F), there is a red arrow mark which indicates the temperature of a healthy person.

The thermometer used in a laboratory has wider range and does not have constriction like a clinical thermometer.

Question b.
What is the difference between heat and temperature?
Answer:
Heat is related to the total kinetic energy of the atoms in a substance while temperature is related to the average kinetic energy of the atoms in the substance. Heat flows from a body at higher temperature to a body at lower temperature. Thus, temperature is a quantity that determines the direction of flow of heat. It is a quantitative measure of the degree of hotness or coldness of a body.

Higher temperature does not mean higher heat content. Suppose a vessel A contains 2 litres of water at 90 °C and a vessel B contains 100 ml of water at 91 °C. Then the heat content of water in A is greater than that of water in B, but the temperature of water in B is higher than that of water in A.

Units of heat:
Heat is usually expressed in calorie, kilocalorie and joule. It can also be expressed in erg as heat is a form of energy.

Question c.
Explain the construction of a calorimeter. Draw the necessary figure.
Answer:

Figure shows the construction of a calorimeter. Like a thermo flask, a calorimeter has two vessels. The inner vessel, made of copper, is (practically) thermally isolated from the surroundings. The outer vessel is made of wood and is covered with a heat resistant lid. The lid has two holes, one for the thermometer and the other for the stirrer. The inner and outer surfaces of the inner vessel are polished for minimizing exchange of heat with the surroundings by radiation. A heat resistant ring covers the inner vessel.

Question d.
Explain why rails have gaps at specific distances.
Answer:
The rails expand in summer due to increase in the temperature of the atmosphere. Also, they expand due to rise in temperature caused by the friction between the rails and the wheels of the running train. If there is no gap between successive rails of a railway line, the rails would bend due to expansion. This bending and twisting of the rails would cause accidents. Hence, a gap is kept between successive rails of a railway line to make provision for their expansion in summer.

Do you know:

Have you seen rails? They are not continuous. A small gap is kept between them at regular intervals. This is shown in the figure. This is kept to accommodate the change in the length of the rails with change in temperature. If this gap is not kept, then the rail will get distorted due to expansion in summer which may lead to accidents.

Similar to rails, the length of bridges can also increase due to expansion in summer. The length of the 18 km long great belt bridge in Denmark increases by 4.7 m in summer. Therefore, provision in made in the construction of the bridges to accommodate this expansion.

Question e.
Explain with the help of formulae the expansion coefficients of liquid and gas.
Answer:
1. A liquid is held in a container. When it is heated, both the container and the liquid expand. The expansion of the container is usually very small compared to that of the liquid in it. Often, it can be ignored.
Suppose a liquid is heated so that its temperature rises by ΔT (very small) and its volume increases from V₁ to V₂. Experimentally, it is found that the increase in volume, V₂ – V₁, is proportional to V₁ and ΔT.
Hence, (V₂ – V₁) α V₁ΔT.
∴ V₂ – V₁ = β V₁ΔT, where β is a constant of proportionality called the volumetric expansion coefficient of the liquid.
β = \(\frac{V_{2}-V_{1}}{V_{1} \Delta T}\).
It is expressed in per °C.
We have V₂ = V₁ + βV₁ΔT = V₁(1 + β ΔT).
β is the increase in the volume of a liquid per unit original volume per unit rise in its temperature.

2. A gas is enclosed in a container. When it is heated at constant pressure, both the container and the gas expand. Suppose a gas is heated at constant pressure so that its temperature rises by ΔT (very small) and its volume increases from V₁ to V₂. Experimentally, it is found that the increase in volume, V₂ – V₁ is proportional to V₁ and ΔT. Hence, (V₂ – V₁) a V₁ΔT.
∴ V₂ – V₁ = β V₁ΔT, where β is a constant of proportionality, the volumetric expansion coefficient, called the constant pressure expansion coefficient.
β = \(\frac{V_{2}-V_{1}}{V_{1} \Delta T}\).
It is expressed in per °C.
We have V₂ = V₁ + βV₁T = V₁(1 + β ΔT).
β is the increase in the volume of a gas per unit original volume per unit rise in its temperature when the pressure is kept constant.

4. Solve the following examples.

Question a.
What must be the temperature in Fahrenheit so that it will be twice its value in Celsius?
Solution:
Data: F = 2 C ∴ C = F/2, F = ?

∴ F – 0.9 F = 32
∴ 0.1 F = 32
∴ F = \(\frac{32}{0.1}\) = 320 °F.

Question b.
A bridge is made from 20 m long iron rods. At temperature 18 °C, the distance between two rods is 0.4 cm. Up to what temperature will the bridge be in good shape?
Solution:
Data: l₁ = 20 m, l₂ – l₁ = 0.4 cm
= 4 × 10^-3 m, T_i = 18 °C, λ for iron = 11.5 × 10^-6/°C
l₂ – l₁ = λl₁ Δt

= \(\frac{400}{23}\) °C = about 17.39 °C
Now, ΔT= T_f – T_i ∴ T_f = T_i + ΔT
∴ T_f = 18 °C + 17.39 °C = 35.39 °C.
The bridge will be in good shape up to 35.39 °C.

Question c.
At 15 °C the height of Eiffel Tower is 324 m. If it is made of iron, what will be the increase in length in cm, at 30 °C?
Solution:
Data: ΔT = 30 °C – 15 °C = 15 °C, l₁ = 324 m, λ for iron = 11.5 × 10^-6/°C l₂ – l₁ = λl₁ ΔT
= 11.5 × 10^-6/°C × 324 m × 15 °C
= 55890 × 10^-6 m
= 55890 × 10^-6 × 10² cm
= 55890 × 10^-4 cm
= 5.589 cm (nearly 5.6 cm)
This is the increase in the length, i.e., the increase in the height of Eiffel Tower.

Question d.
Two substances A and B have specific heats c and 2 c respectively. If A and B are given Q and 4Q amounts of heat respectively, the change in their temperatures is the same. If the mass of A is m, what is the mass of B?
Solution:
Data: c (A) = c, c (B) = 2c,
Q (A) = Q, Q (B) = 4Q, ΔT same,
m (A) = m, m (B) = ?

∴ m(B) = 2m.
This is the mass of B.

Question e.
When a substance having mass 3 kg receives 600 cal of heat, its temperature increases by 10 °C. What is the specific heat of the substance?
Solution:
Data: m = 3 kg = 3000 g,
Q = 600 cal, ΔT = 10 °C, c = ?
Q = mcΔT

= 0.02 cal/(g.°C)
This is the specific heat of the substance.

Can you recall?

Question a.
Which sources do we get heat from?
Answer:

1. Sun
2. earth
3. fuels like wood, coal, petrol
4. electricity
5. atomic energy
6. air.

Question b.
How is heat transferred?
Answer:
Heat is transferred by conduction, convection and radiation.

Question c.
Which effects of heat do you know?
Answer:
Expansion, change of state, rise in temperature, emission of light, burning.

Question d.
Some effects of heat are shown in Fig. What are they?

Answer:
Rise in temperature/boiling, melting, burning, expansion.

Question e.
What are potential and kinetic energies?
Answer:
The energy stored in a body because of its specific state or position is called its potential energy. The energy possessed by a body because of its motion is called it’s kinetic energy.

Project:

Question a.
Collect information about bimetallic strips and discuss in your class how a fire alarm is made using it.

Class 8 Science Chapter 14 Measurement and Effects of Heat Important Questions and Answers

Rewrite the following statements by selecting the correct options:

Question 1.
32°F is equal to …………….. .
(a) 212 °C
(b) 212 K
(c) 273.15 K
(d) 273.15 K
Answer:
32°F is equal to 273.15 K.

Question 2.
-40°C is equal to ………….. .
(a) -40 °F
(b) 40 °F
(c) -8°F
(d) 40K
Answer:
-40°C is equal to -40 °F.

Question 3.
The boiling point of water is ………… .
(a) 212 K
(b) 212 °F
(c) 273.15 K
(d) 32 °F
Answer:
The boiling point of pure water is 212 °F.

Question 4.
Specific heat is expressed in …………… .
(a) J/(kg. °C)
(b) kg/(J C)
(c) J/kg
(d) cal/g
Answer:
Specific heat is expressed in J/(kg.°C).

Question 5.
The freezing point of water is …………….. .
(a) OK
(b) 212°F
(c) 32°F
(d) 0°F
Answer:
The freezing point of water is 32 °F.

Find the odd one out and give the reason:

Question 1.
0°C, 32°F, 273.15K, 212°F.
Answer:
212 °F. This is the boiling point of water; others correspond to the freezing point of water.

Question 2.
373.15 K, 100 °C, 212 °F, 32 °F.
Answer:
32 °F. This is the freezing point of water others correspond to the boiling point of water.

Answer the following questions in one sentence each:

Question 1.
Name the biggest source of heat received by the earth.
Answer:
The Sun is the biggest source of heat received by the earth.

Question 2.
What is the relation between the temperature in °C and the temperature in °F?
F – 32 °C
Answer:
\(\frac{F-32}{9}\) = \(\frac{C}{5}\), where C denotes temperature in °C and F denotes temperature in °F.

Question 3.
Name the quantity expressed in cal/(g.°C).
Answer:
Specific heat is expressed in cal/(g.°C).

Question 4.
State the formula for the coefficient of linear expansion of a solid substance.
Answer:
λ = (l₂ – l₁]) / (l₁ ΔT).

Question 5.
State the formula for the coefficient of areal expansion of a solid.
Answer:
σ = (A₂ – A₁)/ (A₁ ΔT).

Question 6.
State the formula for the volumetric expansion coefficient of a solid.
Answer:
β = (V₂ – V₁) / (V₁ ΔT).

Question 7.
State the relation between λ and σ (if ΔT is very small).
Answer:
σ = 2 λ.

Answer the following questions:

Question 1.
How is heat generated in the Sun?
Answer:
In the interior of the Sun, at the centre, hydrogen nuclei fuse together to form helium nuclei. A lot of heat is generated in this process.

Question 2.
What is geothermal energy?
Answer:
Heat within the interior of the earth, e.g., that coming from the molten core of the earth, is called geothermal energy.
[Note: Volcanoes, geysers, hot springs are sources of this energy.]

Question 3.
What is atomic energy or nuclear energy?
Answer:
Energy released or obtained in nuclear fission or nuclear fusion is called atomic energy or nuclear energy.

Question 4.
Name three sources of chemical energy.
Answer:
Fuels like wood, coal and petrol are sources of chemical energy.

Try this:

1. Take three similar vessels. Let us call them ‘A’, ‘B’ and ‘C’.
2. Fill A with hot water and B with cold water. Put some water from A and B in C.
3. Dip your right hand in A and left hand in B and keep them immersed for 2 to 3 minutes.
4. Now dip both the hands in C. What do you feel?

Even though, both the hands are dipped in water in the same vessel, i.e., water at the same temperature, your right hand will find the water to be cold while the left hand will find it to be hot. What is the reason for this? Think about it.
Answer:
The right hand finds the water cold because it loses heat to water in C. The left-hand feels the water hot because it gains heat from water in C. (This shows that we cannot determine the temperature of an object accurately by simply touching it)

Question 5.
State the units in which temperature is expressed.
OR
What are the units of temperature?
Answer:
Temperature is expressed in °C (degree Celsius), °F (degree Fahrenheit) and K (kelvin).

Question 6.
Draw diagrams to illustrate motion of atoms in a gas and a solid. Also explain the type of motion.
Answer:
Atoms of a gas are comparatively free and move at random. Figures a and b show the velocities of atoms in a gas at high and low temperature, respectively. The direction and the length of the arrows show respectively the direction and the magnitude of the velocity of the atoms. The velocity of atoms in the gas at higher temperature is larger in magnitude than the velocity of atoms in the gas at lower temperature.

The velocities of atoms in a solid are shown by arrows in Fig. (c). The atoms in a solid are tied to one another because of the forces acting between them. This is indicated by drawing springs between adjacent atoms. Because of heat, they oscillate around their fixed mean positions. The higher the temperature of a solid, the greater is their velocity of oscillation.

Try this:

1. Take two steel vessels A and B of the same size.
2. Fill some water in A and double that amount in B. Make sure that the water in both vessels is at the same temperature.
3. Raise the temperatures of water in both vessels by 10 CC using a spirit lamp. Did it take the same time to increase the temperature in the two vessels?
Answer:
No.
You must have required more time to raise the temperature of water in B. This means that for the same increase in temperature, you had to give more amount of heat to B. Thus, even though the water in A and in B have the same temperature, the amount of heat in B is more than that in A.

Question 7.
How are the different units of temperature-related?
Answer:
1. The SI unit of temperature is the kelvin (K). Temperature is also expressed in °C (degree Celsius) and °F (degree Fahrenheit).

Here, C denotes temperature in °C, F denotes temperature in 0F and K denotes temperature in K (kelvin).
[Notes: (i) The unît degree Celsius is named in honour of Anders Celsius (1701 – 44) Swedish astronomer. He devised a temperature scale in 1742.
(ii) The unit degree Fahrenheit is named in honour of Gabriel Daniel Fahrenheit (1686 – 1736) German physicist. He developed the mercury thermometer and devised the temperature scale.
(iii) The unit kelvin is named in honour of William Thomson, 1st Baron Kelvin (of Largs) (1824 – 1907) British physicist and electrical engineer. He made significant contribution in thermodynamics and electromagnetic theory. He proposed a scale of temperature now known as the Kelvin scale or thermodynamic scale.]

Question 8.
What is a liquid (mercury or alcohol) thermometer?
Answer:
A thermometer in which the change in the volume of a liquid (mercury or alcohol) with temperature is used for measurement of temperature is called a liquid thermometer.

Question 9.
Why has mecury been replaced by alcohol in a thermometer?
Answer:
Because mercury is harmful for us, it has been replaced by alcohol in a thermometer.
[Notes: (i) Mercury thermometers are still widely used in laboratories in schools and colleges.
(ii) A thermometer is a device to measure temperature. A thermometer containing mercury in its bulb is called a mercury thermometer. There are other types of thermometer such as a thermocouple thermometer, a platinum resistance thermometer, a thermistor thermometer, etc.]

Question 10.
Describe the construction of mercury thermometer.
Answer:

1. For constructing a thermometer, a thick-walled capillary tube with a uniform bore is taken. The tube has a thin-walled glass bulb at one end.
2. The bulb and a small part of the tube is filled with mercury. The other end of the tube is sealed after removing air from it.
3. The tube is then calibrated and the temperature of the substance can be read with it.

[Note: The range of an alcohol thermometer is different from that of a mercury thermometer.]

Question 11.
How does a mercury thermometer work?
Answer:
1. When the bulb of the thermometer is brought in contact with the substance whose temperature is to be measured, there is an exchange of heat between the substance and the mercury in the bulb.

2. The mercury expands or contracts depending upon whether it gains heat or loses heat. Accordingly there is a rise or fall of the level of mercury in the tube of the thermometer indicating the temperature of the substance when the mercury and the substance are in thermal equilibrium.

Question 12.
Why is the bore of a thermometer made very small?
Answer:
The bore of a thermometer is made very small so that even a slight variation in the temperature may cause noticeable variation in the mercury level in the tube of the thermometer. As a result, the sensitivity of the thermometer increases and even small changes in the temperature can be recorded.

Question 13.
Why does the bulb of a thermometer have a thin glass wall?
Answer:
The bulb of a thermometer is made of a thin glass so that it can easily conduct the heat from the substance in contact with the mercury in the bulb.

Question 14.
Why does a thermometer usually break at the bulb?
Answer:
The bulb of a thermometer has a thin glass wall. Therefore, a thermometer usually breaks at the bulb.

Question 15.
Explain why the capillary tube of a clinical thermometer has a constriction.
Answer:
When the temperature of a patient is measured with a clinical thermometer, the mercury in the bulb expands and rises in the tube. The small constriction in the thermometer prevents the mercury thread from retreating into the bulb. Thus, the patient’s temperature can be read at ease after removing the thermometer from his body.

Question 16.
Explain why a clinical thermometer should not be washed with hot water.
Answer:
A clinical thermometer is constructed for the purpose of recording the temperature of the human body. Hence, its stem is such that it can allow the mercury to rise up to a temperature of about 42 °C. The temperature of hot water may be more than 42 °C. Therefore, when a clinical thermometer is washed with hot water, mercury will not have enough room for expansion and the thermometer would break.

[Note: (1) A digital thermometer has a sensor that detects the heat coming out from the body directly and displays the temperature.
(2) The maximum-minimum temperature has two scales, one against each arm of the thermometer. One scale indicates the maximum temperature reached (generally during the day) and the other scale indicates the minimum temperature reached (generally during the night).]

Question 17.
Explain what happens when there is exchange of heat between two objects.
Answer:
When there is an exchange of heat between a hot object and a cold object, the temperature of the hot object falls and the temperature of the cold object rises. If this system of two objects is isolated from the surroundings so that no heat enters or leaves the system, then, heat lost by the hot object = heat gained by the cold object. After some time, the average kinetic energies of the atoms in the two objects become equal, i.e., the two objects attain the same temperature.

Question 18.
Define specific heat.
Answer:
The specific heat of an object (substance) is the amount of heat required to increase the temperature of unit mass of that substance through one degree.

Question 19.
Write the formula for specific heat. Hence, obtain its unit.
Answer:
Specific heat of a substance,
c = \(\frac{Q}{m\left(T_{\mathrm{f}}-T_{\mathrm{i}}\right)}\), where m is the mass of the substance and Q is the amount of heat supplied to the substance to increase its temperature from Ti to Tf.

The SI unit of heat is the joule (J), that of mass is kg and that of temperature is kelvin (K).
∴ The SI unit of specific heat = \(\frac{\mathrm{J}}{(\mathrm{kg} \cdot \mathrm{K})}\)
[Note: Specific heat is also expressed in J/(kg°C) and cal/(g°C).]

Question 20.
The specific heat of aluminium is 0.21 cal/(g°C). What do you understand by this statement?
Answer:
The amount of heat required to raise the temperature of 1g of aluminium through 1 °C is 0.21 cal.

Question 21.
The specific heat of gold is 0.03 cal/(g°C). Express it in J/(kg°C).
Answer:
1 cal = 4.18 joules (J)
1 gram = 10^-3 kg
∴ 1 cal/(g°C) = 4.18 J/(10-3 kg°C)
= 4180 J/(kg°C)
∴ 0.03 cal/(g°C) = 0.03 × 4180 J/(kg°C)
= 125.4 J/(kg °C)

Question 22.
Arrange the following materials in increasing order of specific heat: aluminium, gold, iron, water.
Answer:
Gold, iron, aluminium, water.

Use your brain power!

Question 1.
Why does your mother put folded cloth strips soaked in cold water on your forehead when you have high fever?
Answer:
To remove heat quickly from our body and thereby lower the temperature of the body (as water has high specific heat).

Question 2.
Why is the calorimeter made of copper?
Answer:
Copper is a good conductor of heat and has low specific heat. Also copper is durable and not highly reactive.

Question 23.
How will you determine the specific heat of a metal using a calorimeter?
OR
Describe the experiment to determine the specific heat of iron using an iron ball, calorimeter and water.
Answer:
1. Find the mass (m_i) of the iron ball.
2. Find the total mass (m_c) of the calorimeter (metal container) and the stirrer.

3. Fill the calorimeter to two-thirds of its capacity with water and find its mass (m’_c) along with the stirrer. Hence, find the mass (m_w) of the water in the calorimeter (m_w = m’_c – m_c).
4. Keep the calorimeter in the wooden box and note the temperature (T₁) of the water in the calorimeter with the thermometer.

5. Suspend the iron ball in water in a beaker. Heat the beaker so that the water starts boiling. Note the temperature (T₂) of the boiling water.
6. Transfer the iron ball quickly to the calorimeter and cover the calorimeter with the lid immediately.

7. Stir the water in the calorimeter gently and continuously for uniformity of temperature and note the maximum temperature (T₃) attained by the mixture.

8. Find the specific heat capacity of iron using the following formula:
heat lost by the iron ball = heat gained by the calorimeter, stirrer and water
[assuming that there is no exchange of heat between the system (calorimeter, stirrer, water and iron ball) and the surroundings].

where cc = specific heat of the material of the calorimeter and stirrer and c_w = specific heat of water.
Hence, the specific heat of iron (c_i) can be determined when other quantities are known.

Question 24.
Why is a calorimeter used in the study of the exchange of heat between a solid and liquid or between two liquids?
Answer:
When a hot body is kept in contact with a cold one, there is an exchange of heat between the two. Hence, the temperature of the hot body decreases while that of the cold body increases till both the bodies attain the same temperature. During this process, if there is no exchange of heat between the surrounding and the bodies, the heat lost by the hot body is equal to the heat gained by the cold body.

As a calorimeter ensures that there is hardly any exchange of heat between the contents of the calorimeter and the surroundings, the calorimeter is used in the study of the exchange of heat between a solid and liquid or between two liquids.

Question 25.
Explain why the inside and outside of a calorimeter are polished.
Answer:

1. A calorimeter is used for the measurement of heat. Hence, it is essential to minimize the exchange of heat between the vessel and the surroundings.
2. A polished surface is a good reflector of heat. Hence, by polishing the inside and outside of a calorimeter, the loss or gain of heat due to radiation is reduced to a considerable extent.

Question 26.
Explain with the help of a formula the coefficient of linear expansion of a solid.
Answer:
Suppose a rod of length l₁ at temperature T₁ is heated to temperature T₂ such that ΔT = T₂ – T₁ is very small. Let l₂ be the length of the rod at temperature T₂.
Experimentally, it is found that the increase in the length of the rod (linear expension), l₂ – l₁, is proportional to l₁ and ΔT. Therefore, (l₂ – l₁) α, l₁ΔT
∴ l₂ – l₁ = λl₁ ΔT, where X is the constant of proportionality, called the coefficient of linear expansion of the solid.
λ = \(\frac{l_{2}-l_{1}}{l_{1} \Delta T}\) It is expressed in per °C.
We have l₂ – l₁ + λΔT = l₁ (1 + λΔT).

Question 27.
Define coefficient off linear explansion of a solid. Write the formula for it and obtain its unit.
Answer:
Coefficient of linear expansion of a solid is defined as the increase in the length of a rod of the solid per unit initial length per unit rise in its temperature.
Coefficient of linear expansion of a solid,
λ = \(\frac{l_{2}-l_{1}}{l_{1} \Delta T}\), where l₁ and l₂ are respectively the initial and final length of the rod of the solid and ΔT is the rise in its temperature.
Unit of λ = \(\frac{\text { unit of length }}{\text { unit of length } \times \text { unit of temperature }}\)

Question 28.
The coefficient of linear expansion of silver is 18 ×10^-6 per °C. What do you understand by this statement?
Answer:
If the temperature of a silver rod of length lm is increased by 1 °C, the length of the rod increases by 18 × 10^-6 m.

Question 29.
Explain with the help of a formula the coefficient of areal expansion of a solid.
Answer:
Suppose a sheet of a solid with surface area A₁ at temperature T₁ is heated to temperature T₂ such that ΔT = T₂ – T₁ is very small. Let A₂ be the surface area of the sheet at temperature T₂. Experimentally, it is found that the increase in the surface area of the sheet (areal expansion), A₂ – A₁, is proportional to A₁ and ΔT. Therefore,
(A₂ – A₁)α A₁ ΔT
∴ A₂ – A₁ = σ Al₁ΔT, where a is the constant of proportionality, called the coefficient of areal expansion of the solid.
σ = \(\frac{A_{2}-A_{1}}{A_{1} \Delta T}\). It is expressed in per °C.
We have A₂ = A₁ + σA₁ΔT = A₁ (1 + σΔT).
σ is the increase in the area of a solid per unit original area per unit rise in its temperature.
[Note: Consider a thin square metal plate of length l. Area of one face of the plate = A = l₂. Suppose the plate is heated so that the rise in its temperature is ΔT (assumed to be very small). Then in the usual notation, Δl = l λΔT and ΔA =
AσΔT = l² σΔT. Also, ΔA = (l + Δl)² – l² = l² + 2l.Δl + Δl² – l2 = 2l.Δl + Δl² . As Δl² << 2l.Δl, we can write ΔA = 2l.Δl(approximately)
∴ ΔA = 2l(l λΔT) = 2l²λΔT but ΔA = l²σΔT
∴ σ = 2.λ]

Question 30.
Explain with the help of a formula the volumetric expansion coefficient of a solid.
Answer:
Suppose a solid with volume V₁ at temperature T₁ is heated to temperature T₂ such that T₁ = T₂ – T₁ is very small. Let V₂ be the volume of the solid at temperature T₂. Experimentally, it is found that the increase
in the volume of the solid (volumetric expansion), V₂ – V₁, is proportional to V₁ and ΔT. Therefore, (V₂ – V₁)α V₁ΔT.
∴ V₂ – V₁ = βV₁ΔT, where β is the constant of proportionality, called the volumetric expansion coefficient of the solid.
β = \(\frac{V_{2}-V_{1}}{V_{1} \Delta T}\) It is expressed in per °C.
We have V₂ = V₁ + βV₁ ΔT = V₁ (1 + βΔT).
is the increase in the volume of a solid per unit original volume per unit rise in its temperature.
[Note: It can be shown that β = \(\frac{3}{2}\) σ 3λ.]

Question 31.
Obtain an expression for the variation of the density of a solid with temperature.
Answer:

As the temperature increases, density decreases.

Use your brain power!

Question 1.
Which use of the expansion of liquids in daily life do you know?
Answer:
Use of a thermometer. The effect of heat on water is somewhat different from that for other liquids. This is called anomalous behaviour of water. We are going to learn about it in higher standard.

Can you recall?

Expansion of gases:

A gas does not even have a fixed volume. Gas expands on heating but if the gas is kept in a closed box, its volume cannot increase but its pressure increases. This is shown in Fig. Observe Fig. and find out answers to the questions.

Question 1.
Using the formula density = mass/volume, explain what will be the effect of heat on the gas kept in a closed bottle.
Answer:
The density of the gas will remain the same as there is no change on the mass and volume of the gas.

Question 2.
If the bottle is not closed but has a movable piston attached to its open end (see the figure), what will be the effect of heating the gas in the bottle?
Answer:
The piston will move upwards as the gas expands.
Therefore, the expansion of a gas is measured by keeping its pressure constant.

Use your brain power!

Question 1.
The density of a gas decreases on heating. Which of the pictures in Fig. makes use of this?
Answer:
Students should be able to answer this question.

Write short notes on the following:

Question 1.
The Celsius temperature scale:
Answer:
In this case, the temperature at which pure ice melts at normal atmospheric pressure is taken as zero degree (0°C) and the temperature at which pure water boils at normal atmospheric pressure is taken as hundred degree (100 °C). The interval between them is divided into loo equal parts. Each part corresponds to a temperature difference of 1 °C.

Question 2.
The Fahrenheit temperature scale:
Answer:
In this case, the normal melting point of pure ice is taken as 32 °F and the normal boiling point of pure water is taken as 212 °F. The interval between these two points is divided into 180 equal parts. Each part corresponds to a temperature difference of 1°F. If C is the temperature of a body on the Celsius scale and F is the corresponding temperature on the Fahrenheit scale, the two are related by
C = \(\frac{5}{9}\) (F – 32) or F = \(\frac{9}{5}\) C + 32.

Question 3.
The Kelvin temperature scale:
Answer:
In this case, the melting point of pure ice at normal atmospheric pressure is taken as 273.15 kelvin (273.15 K) and the boiling point of pure water at normal f atmospheric pressure is taken as 373.15 I kelvin (373.15 K). The lowest possible temperature (called the absolute zero) on this scale corresponds to -273.15 °C.

Give scientific reasons:

Question 1.
We heat the neck of a glass bottle in order to remove the firmly fitted stopper.
Answer:
When we heat the neck of the glass bottle, it expands. Due to this, the stopper becomes loose and can be removed with ease.

Question 2.
A clinical thermometer has to be jerked before re-use.
Answer:
The constriction above the bulb of the clinical thermometer prevents the mercury thread once risen from falling down to the bulb. Hence, in order to force the mercury thread back into the bulb, the 1 clinical thermometer has to be jerked before re-use.

Question 3.
Instead of the mercury thermometer, alcohol thermometer is used for measurement of very low temperature.
Answer:
Mercury freezes at – 39 °C and turns to a solid. Hence, the mercury thermometer cannot be used to measure temperature below -39°C. The freezing point of alcohol is -117°C. Hence, the alcohol thermometer is used for i measurement of very low temperature.

Solve the following examples:

Question 1.
The normal armpit temperature in humans is 98.6 °F. What is this temperature in (i) degree Celsius (ii) kelvin ?
Solution:
Data: F = 98.6 °F, C = ?, K = ?

(ii) K = C + 273.15
= 37 + 273.15 = 310.15 K.

Question 2.

Find the heat needed to raise the temperature of 2.5 kg of water from 30 °C to 40 °C. Write the answer in calorie as well as joule.
Solution:
Data: m = 2.5 kg = 2500 g,
ΔT = 40 °C-30 °C, Q = ?
Heat needed to raise the temperature of 1 g of water through 1°C is 1 calorie.
∴ Q = 2500 × 10 = 25000 calories
Now, 1 calorie = 4.18 joules
∴ Q = 25000 × 4.18 joules = 104500 joules
Heat needed, Q = 25000 calories = 104500 joules.

Question 3.
If the temperature of water rises by 5 °C when 500 cal of heat is supplied to it, what is the mass of water?
Solution:
Mass of water = \(\frac{500}{5}\) = 100 g.

Question 4.
How much heat is required to raise the temperature of 500 g of mercury from 20 °C to 100 °C? [Specific heat of mercury = 0.033 kcal/(kg °C)]
Solution:
Data: m = 500 g = 0.5 kg,
T₁ = 20 °C,
T₂ = 100 °C, c = 0.033 kcal/(kg . °C), Q = ?
Q = mc (T₂ – T₁)
= 0.5 kg × 0.033 kcal/(kg . °C) × (100 °C – 20 °C)
= 0.5 × 0.033 × 80 kcal
= 0.033 × 40 kcal
∴ Q = 1.32 kcal
Heat required = 1.32 kcal.
[Note: 1kcal/(kg-°C) = 1 cal/(g.°C)]

Question 5.
A certain mass of water at 84 °C is poured into an equal mass of water at 24 °C. What will be the resulting temperature of the mixture ?
Solution:
Data: mx = m2 = m (say),
T₁ = 84 °C, T₂ = 24 °C, T = ?
Heat lost by the hot water = heat gained by the cold water

Resulting temperature of the mixture = 54 °C.

Question 6.
A bucket contains 8 kg of water at 20 °C. When 4 kg of hot water is mixed with it, the temperature of the mixture becomes 40 °C. Calculate the temperature of the hot water. (Ignore the heat absorbed by the bucket.)
Solution:
Data: m₁ = 8 kg, T₁ = 20 °C, m₂ = 4 kg, T = 40 °C, T₂= ?
Heat lost by the hot water = heat gained by the cold water (ignoring the heat absorbed by the bucket)
∴ m₂c (T₂ – T) = m₁c (T – T₁)
∴ 4 kg × c × (T₂ – 40°C)
= 8 kg × c × (40°C – 20°C)
∴ T₂ – 40°C = 2 × 20°C = 40°C
∴ T₂ = 40 °C + 40 °C = 80 °C
Temperature of the hot water = 80 °C.

Question 7.
A blacksmith plunges a 2 kg horseshoe at 400 °C into 1 kg of water at 20 °C. Find the maximum temperature of the water. [Specific heat of iron = 0.11 kcal/(kg-°C)]
Solution:
Data: mx = 2 kg,
c₁ = 0.11 kcal/(kg.°C), T₂ = 400 °C, m₂ = 1 kg,
c₂ = 1 kcal/(kg.°C), T₂ = 20 °C, T = ?
Heat lost by the horseshoe = heat gained by the water
∴ m₁c₁ (T₁ – T) = m₂c₂(T – T₂)
∴ 2 kg × 0.11 kcal/(kg.°C) × (400 °C – T)
= 1 kg × 1 kcal/(kg.°C) × (T – 20 °C)
∴ 0.22 × (400 °C – T) = T – 20 °C
∴ 1.22 T= 108 °C
∴ T = \(\frac{108}{1.22}\)°C = 88.52 °C
Maximum temperature of the water = 88.52 °C.

Question 8.
A copper sphere of mass 500 g is heated to 100 °C and then introduced into a copper calorimeter containing 100 g of water at 20 °C. Find the maximum temperature of the mixture, if the mass of the calorimeter is 100 g and the specific heat of the calorimeter is 0.1 cal/(g.°C).
Solution:
Data: m = 500 g, c = 0.1 cal/(g.°C), T’= 100 °C, m₁ = 100 g, c₁ = 1 cal/(g.°C), T₁ = 20°C, m₂ = 100 g, c₂ = 0.1 cal/(g.°C), T₂ = 20 °C, T= ?
Heat lost by the sphere = heat gained by the water and the calorimeter.
∴ mc (T’ – T) = m₁c₁ (T – T₁) + m₂c₂ (T – T₂)
∴ 500 g × o.l cal/(g.°C) × (100 °C – T)
= 100 g × 1 cal/(g.°C) × (T – 20 °C) + 100 g × 0.1 cal/(g.°C) × (T – 20 °C)
∴ 50 (100 °C – T) = 100 × (T – 20 °C) + 10 × (T – 20 °C)
∴ 50 (100 °C – T) = 110 × (T – 20 °C)
∴ 500 °C – 5T = 11T – 220 °C
∴ 16T = 720 °C
∴ T = \(\frac{720^{\circ} \mathrm{C}}{16}\) = 45 °C
Maximum temperature of the mixture = 45 °C.

Question 9.
A metal rod 1.8 m long, increases ( in length by 1.4 mm, when heated from 0 °C to 50 °C. Find the coefficient of linear expansion of the metal.
Solution:
Data: l₁ = 1.8 m, l₂ – l₁ = 1.4 mm = 1.4 × 10^-3 m.
T₁ = 0 °C, T₂ = 50 °C.
l₂ – l₁ = l₁ λ (T₂ – T₁)
∴ The coefficient of linear expansion of the metal is

Question 10.
A thin metal disc of surface area 500 cm2 at 0 °C is heated to 40 °C. Find the increase in the surface area of the disc. (σ = 4 × 10^-5 °C ^-1)
Solution:
Data: A₁ = 500 cm², T₁ = 0 °C,
T₂ = 40 °C, σ = 4 × 10^-5 °C^-1, A₂ – A₁ = ?
The increase in the surface area of the disc is
A₂ – A₁ = A₁σ(T₂ – T₁)
= (500 cm²) (4 × 10^-5 °C^-1) (40 °C – 0 °C)
= 500 × 4 × 10^-5 × 40 = 0.8 cm².

Question 11.
The surface area of a metal plate is 2.4 × 10^-2m² at 20 °C. When the plate is heated to 185 °C, its area increases by 0.8 cm². Find the coefficient of areal expansion of the metal.
Solution:
Data: A₁ = 2.4 × 10^-2 m²,
T₁ = 20 °C, T₂ = 185 °C, ΔA = 0.8 cm² = 0.8 × 10^-4 m², σ = ?
ΔA = A₂ – A₁ = A₁ σ(T₂ – T₁)
∴ The coefficient of areal expansion of the metal is

Question 12.
A lead bullet has a volume of 25 cm³ at 0 °C, and 25.21 cm³ at 90 °C. Find the volumetric expansion coefficient of lead.
Solution:
Data: V₁ = 25 cm³, T₁ = 0 °C,
V₂ = 25.21 cm³, T₂ = 90 °C
T₂ – T₁ = 90 °C – 0 °C = 90 °C β = ?

The volumetric expansion coefficient of lead is 9.333 × 10^-5 °C^-1.

Example Questions for practice:

Question 1.
The temperature of a body is 30 °C. Express it in (i) degree Fahrenheit (ii) kelvin.
Answer:
86 °F, 303.15 K

Question 2.
The temperature of a body is 283.15 K. Express it in °C and °F.
Answer:
10 °C, 50 °F

Question 3.
The temperature of a body is 68 °F. Express it in °C and K.
Answer:
20 °C, 293.15 K

Question 4.
Find the heat needed to raise the temperature of 5 kg of water from 20 °C to 25 °C. Write the answer in calorie as well as joule.
Answer:
25 × 10³ cal, 1.045 × 10⁵ J

Question 5.
When a substance having mass 2 kg absorbs 2000 cal of heat, its temperature increases by 10 °C. Find the specific heat of the substance.
Answer:
0.1 cal/(g.°C)

Question 6.
Find the heat needed to raise the temperature of 100 g of a metal through 10 °C if the specific heat of the metal is 0.1 cal/g. °C.
Answer:
100 cal

Question 7.
If water of mass 80 g and temperature 40 °C is mixed with water of mass 20 g and temperature 25 °C, what will be the maximum temperature of the mixture?
Answer:
37 °C

Question 8.
A metal rod 2.5 m long, increases in length by 1.25 mm when it is heated from 10 °C to 60 °C. Find the coefficient of linear expansion of the metal.
Answer:
1 × 10^-5 °C^-1

Question 9.
The surface area of a metal plate is 2 × 10^-2 m² at 10 °C. When the plate is heated to 60 °C, its area increases by 0.2 m². Find the coefficient of areal expansion of the metal.
Answer:
2 × 10^-5 °C^-1

Question 10.
A metal ball has volume 50 cm3 at 0 °C and 50.4 cm3 at 100 °C. Find the volumetric expansion coefficient of the metal.
Answer:
8 × 10^-5 °C^-1

Project:

Ref. Project. Useful information:
A bimetallic strip: A bimetallic strip consists of two strips of equal lengths but of different metals rivetted together. At room temperature the strip is straight.

Question 1.
The principle on which a bimetallic strip works:
Answer:
When two different metal strips of the same length at a given temperature are heated to the same higher temperature, they expand in different proportion.
A bimetallic strip of brass and iron is straight at room temperature. The expansion of brass is nearly 1.5 times that of iron. Hence, when this bimetallic strip is heated, it bends, making the iron side concave.

Question 2.
How a bimetallic strip is used in fire alarm:
Answer:
A bimetallic strip of brass and iron is

connected to a battery and an electric bell as shown in the diagram. One terminal of the bell is connected to a screw which is at a very small distance from the iron side of the strip. In case, there is an accidental fire, the bimetallic strip bends towards iron and touches the screw. Thus, the circuit is completed and the bell rings, thereby warning the people of the accidental fire.

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 8 Pollution Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 8 Science Solutions Chapter 8 Pollution

Class 8 Science Chapter 8 Pollution Textbook Questions and Answers

1. Following are some statements about pollution. Which type of pollution do those express:

Question a.
Fog seems to be appearing in Delhi during day hours.
Answer:
Air pollution-Smog
(The sentence should have the word Smog and not fog. Smog is fog with smoke. Only fog cannot be polluting, but the smog is.)

Question b.
Many times, vomiting and dysentery occurs after eating ‘panpuri’.
Answer:
Water pollution-Contaminated food and water due to bacteria or virus

Question c.
Problem of sneezing occurs sometimes during visit to garden.
Answer:
Air pollution due to pollens

Question d.
Crop does not grow up in some areas.
Answer:
Soil pollution

Question e.
People living in the busy squares face the problems like short breathing and other respiratory problems.
Answer:
Air pollution due to traffic

2. Read the passage and identify the sentences expressing types of pollution.

Question a.
Nilesh is a student of Std. VII and lives in urban area. It takes about an hour to go to the school by bus. He faces the heavy traffic of two wheelers, four wheelers, rickshaws, buses while going to school. He is facing the problem of asthma since last few days, Doctors recommended him to stay away from urban area. Since then, his mother sent him to the village of his maternal uncle, Nilesh saw the heaps of garbage at many places in village. Foul smell of human and animal wastes was present at many places. Blackish water with foul smell was flowing in a stream. He developed some abdominal disease within few days.
Answer:

1. It takes about an hour to go to the school. (Due to traffic jam, Nilesh is spending more time in polluted, contaminated air.)
2. He faces the heavy traffic. (Large scale combustion of fossil fuel.)
3. He is facing the problem of asthma. (Air pollution – Harmful to human health.)
4. The heaps of garbage at many places. (Solid waste – Land pollution.)
5. Foul smell of human and animal wastes. (Biological pollution, air pollution.)
6. Blackish water with foul smell was flowing in a stream. (Improper sewage management – Water pollution.)
7. He developed some abdominal disease within few days. (Water pollution – Effect on human health.)

3. Match the pairs from ‘A’ and ‘B’ columns and explain the effect of pollution on human health.

Question a.

Column ‘A’	Column ‘B’
1. Water containing cobalt	a. Mental retardation
2. Methane gas	b. Paralysis
3. Water containing lead	c. Inflammation of lungs
4. Sulphur dioxide	d. Skin cancer
5. Nitrogen dioxide	e. Irritation of eyes

Answer:

Column ‘A’	Column ‘B’
1. Water containing cobalt	b. Paralysis
2. Methane gas	d. Skin cancer
3. Water containing lead	a. Mental retardation
4. Sulphur dioxide	e. Irritation of eyes
5. Nitrogen dioxide	c. Inflammation of lungs

4. True or false.

Question a.
Water does not get polluted by washing the clothes in running water of river.
Answer:
False. (Even if washing of soiled clothes is done in running water, it will cause pollution as the dirt and the waste materials will be added to water. This certainly will cause water pollution.)

Question b.
More the use of electric appliances, more will be the pollution.
Answer:
True. (Most of the electricity is generated in India by burning coal. The power generation plants thus cause lots of air pollution. More the electricity is used by using more appliances, there will be more pollution. However, only power generation through solar energy cannot cause pollution.)

5. Answer the following:

Question a.
What is pollution?
Answer:
Contamination of natural environment that can harmfully affect the environment is called pollution.

Question b.
What are Pollutants?
Answer:
The products which affect the normal functioning of ecosystem and have an adverse effect on plants, animals and humans are called pollutants.

Question c.
What is acid rain?
Answer:
1. When rainwater contains harmful amounts of nitric and sulphuric acids, it is called acid rain.
2. Burning of fossil fuels such as coal, wood, petroleum, etc. releases nitrogen oxide and sulphur oxide into the atmospheric air.
3. Since these oxides are soluble in water, they dissolve in rainwater. Nitrogen and sulphur oxides dissolved in large quantities of water vapour form acids like nitric acid, nitrous acid, sulphurous acid and sulphuric acid.
4. These acids mix with mist, drops of rainwater and snow. They change their composition and fall back on the ground in the form of acid rain.
5. Effects of acid rain are as follows:

• Increase in the acidity of soil and water bodies.
• Damage to the trees.
• Water becomes unsuitable for fish and wildlife.
• Buildings, statues, sculptures, bridges, monuments and fences are corroded due to acid rain. Thus, acid rain damages our national assets.
• Acid rain affects agriculture and crop lands.

Question d.
What is greenhouse effect?
Answer:

1. Greenhouse effect is the ; phenomenon due to which global warming and climate change occur.
2. The earth receives solar energy in the form of heat from the sun. The surface of earth absorbs this heat and reflects it back to the atmosphere as infrared radiation. Some of this heat energy goes directly into space.

Question e.
Which are visible pollutants known to you?
Answer:
1. The polluting substances that are seen easily with the naked eyes can be called as visible pollutants. E.g. Solid wastes, plastic articles, plastic bags, the suspended things in the water, metal refuse, etc.

Question f.
Which are invisible pollutants?
Answer:
The pollutants which are completely dissolved in water or mixed in the air, cannot be seen and hence they can be called invisible pollutants. Since they are not seen, we remain unaware about the presence of these pollutants. E.g. the insecticides spread f on the crops. Aerosols, many hazardous gases in the air, toxic compounds that are totally soluble in water, etc.

6. Answer the following.

Question a.
Give two examples of each of water, soil and air pollution from your residential area.
Answer:
Air pollution:

1. New buildings are constructed. Old structures are demolished. This is creating lots of dust pollution. The air is full of particulate matter.
2. The number of vehicles on the road has tremendously increased. This causes smoky environment.

Water pollution:

1. The sea shows lots of floating plastic and decaying flowers, etc. When beaches are visited it is a common sight.
2. Many fishes are seen dying in great numbers and are washed off to the shore.

Soil pollution :

1. Everywhere garbage heaps are seen. In that plastic bags, needles, old medicine vials and cartons are seen in abundance.
2. The sludge brought by rainwater is spread everywhere and that causes stink.

Question b.
How does the pollution occur due to vehicles? Give the names of vehicles causing least pollution.
Answer:

1. More than 50% of the air pollution is caused by vehicular traffic.
2. Particulate matter, unburnt hydrocarbons, CO, nitrogen oxides and carcinogenic hydrocarbons are present in the automobile exhausts.
3. Fossil fuels like petrol, diesel, natural gas, gasoline, etc. which are burnt to run the automobiles lead to the emission of CO₂ and other gases.
4. Therefore, vehicles are said to be the major contributors to air pollution.
5. The only vehicle which is non¬polluting is bicycle. The four-wheelers which are battery operated are also manufactured recently.

These two types of vehicles are eco-friendly. The cars that run on C.N.G. are also said to be lesser polluting.

Question c.
What are natural reasons causes for water pollution?
Answer:
The natural causes of the water pollution:
1. If organic pollutants are added to the water there is an overgrowth of weeds such as Eichhornia. The growth of algae also makes the water unsuitable for consumption. These aquatic plants release oxygen during daytime but by night they require oxygen thus depleting the dissolved oxygen level. The natural characters of water are then changed.

2. The decomposing matter when added to the water make it polluted and stinking.

3. Due to deposition of sludge or eroded soil, the rivers change their path and divert from original flow. The currents are also changed. Deposition of sludge makes the water polluted.

4. Due to soil erosion, surrounding the water bodies, the microbes, bacteria, protozoans and the worms and larvae of nematodes enter the water causing severe biological pollution. Many inorganic pollutants are also added to the water. The fungand bacteria present in the water make it non-potable. Such water spreads water-borne diseases.

Question d.
Suggest four preventive measures for air pollution.
Answer:
The following methods are adopted to control air pollution from the industries:

1. The source discharge is diluted by tall chimneys.
2. There are source correction methods like changing the raw material, equipment modification, process modification, etc.
3. Effective pollution controlling equipment like dust collectors, electrostatic precipitators, wet scrubbers, etc. should be used.
4. There should be ban and control over atomic tests and chemical weapons on the international level.

Question e.
Explain relation between greenhouse effect and global warming.
Answer:
Because of greenhouse effect, there is increase in the global temperature. The heat on the earth remains trapped due to envelope of greenhouse gases. The percentage of carbon dioxide and methane is constantly increasing and hence there is increase in the temperature too. Thus the greenhouse effect is directly related to the global warming.
Effects of this relation between greenhouse effect and global warming are as follows:

1. The polar ice caps and the glaciers at both the poles are melting due to increased temperature.
2. The oceans’ water is rising due to this melted ice. The sea level rise is causing coastal land submergence. The islands at various regions are threatened of drowning.
3. Many species of living organisms are already extinct due to global warming. The rest are also threatened.
4. Wild animals are showing weird migrations. Polar bear is endangered.
5. The increased temperature of the oceanic water is causing many changes in the tides and currents. This results into increased occurrence of cyclones, hurricanes and cloud bursting. The natural disasters are rising in last decade.
6. The agricultural production is decreasing. The regions with less rainfall are facing draughts.

Question f.
Construct two slogans each on air, water and soil pollution.
Answer:
Air pollution:

1. Be a part of the solution and not part of pollution.
2. Show your care, clean your air.

Water pollution:

1. Water, water everywhere, Not a drop to drink. The pollution is making all the water stink.
2. Save the fish and the little turtle. Don’t throw plastic or it will encircle.

Soil Pollution:

1. Don’t be mean, keep environment clean.
2. Let’s keep land clean, together only we can win.

7. Classify the following pollutants into natural and manmade categories.

Question
Classify the following pollutants into natural and manmade categories.
Sewage, dust, pollen grains, chemical fertilizers, vehicular smoke, algae, pesticides, waste of animals and birds.
Answer:

Man-made	Natural
1. Sewage	1. Dust (Natural)
2. Dust (Construction related)	2. Pollen grains
3. Chemical fertilizers	3. Algae
4. Vehicular smoke	4. Waste (Excreta) of animals and
5. Pesticides

Project:

Question 1.
Visit the water testing laboratory in your area and collect the information about tests for checking the purity of water.

Question 2.
Visit the square having heavy traffic in your area and report the pollution at different times of day and find out the duration of maximum pollution.

Class 8 Science Chapter 8 Pollution Additional Important Questions and Answers

Rewrite the sentences after filling the blanks:

Question 1.
Natural pollutants are destroyed in due course of time by …………. .
Answer:
Natural pollutants are destroyed in due course of time by nature’s rule.

Question 2.
Air pollutants with ……….. cause colour change in paints, oil paintings, nylon, etc.
Answer:
Air pollutants with sulphur cause colour change in paints, oil paintings, nylon, etc.

Question 3.
Boards indicating the …………. are displayed in busy squares in metro cities.
Answer:
Boards indicating the air quality index are displayed in busy squares in metro cities.

Question 4.
Soil ………… decreases due to pollution.
Answer:
Soil fertility decreases due to pollution.

Question 5.
Problem of …………… pollution increases due to soil pollution.
Answer:
Problem of water pollution increases due to soil pollution.

State whether the following statements are True or False. Explain your statement:

Question 1.
Polluted water is responsible for diseases such as cholera, hepatitis, typhoid, skin diseases and diseases of the alimentary canal.
Answer:
True. (The water sources if they are contaminated with biological pollutants such as bacteria, viruses or protozoans, can cause variety of water-borne diseases.)

Question 2.
When water is mixed with natural or artificial unwanted material, the dissolved oxygen level of such water increases.
Answer:
False. (When water is mixed with natural or artificial unwanted material, the dissolved oxygen level of such water decreases. This causes harm to the resident animals. However when aquatic weeds and algae outgrow in number it causes rise in oxygen only during day time.)

Question 3.
Though any amount of pollutants are added to the soil, the toxic substances do not leach into water.
Answer:
False. (The toxic substances added to the soil can leach in the groundwater and cause water pollution.)

Identify the odd term:

Question 1.
Industrialization, Population explosion, Mining, Vehicular transport, Dust storms.
Answer:
Dust storms (All others are man-made causes environmental degradation.)

Question 2.
Poisoning, asthma, Silicosis, respiratory diseases.
Answer:
Silicosis (All others are effects of methane.)

Question 3.
Irritation of eyes, respiratory tract, excess mucus, mental weakness
Answer:
Mental weakness (All other are effects of sulphur dioxide.)

Question 4.
Volcanic eruption, Earthquake, Atomic explosion, Forest fires.
Answer:
Atomic explosion (All others are natural causes of air pollution.)

Question 5.
Uranium, Sulphur, Thorium, Plutonium.
Answer:
Sulphur (All others are elements which are used in the production of atomic energy.)

Consider the relation between the items in the first pair and write the correlation for second pair:

Question 1.
Industrialization: Sulphur compounds : :…………………. : Lead compounds
Answer:
Use of fuels/Transportation

Question 2.
City where smoke and soot caused it to be called black city : Petersburg : : Indian city where worst ever industrial accident has occurred : ……………….
Answer:
Bhopal

Question 3.
Arsenic and Cadmium : Inorganic water pollutants : : Weedicides and insecticides : ………….
Answer:
Organic water pollutants.

Write definitions:

Question 1.
Air pollution.
Answer:
Contamination of air by toxic gaseous and particulate pollutants in concentration which is harmful to human beings and his surroundings is called air pollution.

Question 2.
Water pollution.
Answer:
When toxic and unwanted substances enter, dissolve or remain suspended in the water bodies deteriorating the quality of water and affecting the aquatic ecosystem, then it is known as water pollution.

Question 3.
Soil pollution.
Answer:
Soil pollution is the phenomenon caused due to natural or man-made causes, which occurs when there are changes in its physical, biological and chemical properties of the soil leading to decreased fertility due to either natural or man-made reasons.

Distinguish between the following:

Question 1.
Degradable and Non-degradable pollutants:

Degradable pollutants	Non-degradable pollutants
1. Degradable pollutants can degrade on their own after some time.	1. non-degradable pollutants cannot degrade on their own.
2. Degradable pollutants are usually acted upon by microorganisms to reduce them to inorganic substances.	2. non-degradable pollutants are not acted upon by microorganisms and hence are not reduced to inorganic substances.
3. Degradable pollutants are not accumulated in nature.	3. non-degradable pollutants accumulate in nature and remain there for a long period of time.
4. Degradable pollutants emit foul odour when they are being decomposed.	4. non-degradable pollutants may not emit foul odour as they are not decomposed.
5. Vegetables and fruits, food refuse, organic matter, etc. form degradable pollutants.	5. Metals, plastic, glass, etc. form non-degradable pollutants.

Question 2.
Industrial waste and Domestic waste:

Industrial waste	Domestic waste
1. Most of the industrial waste contains non-degradable pollutants.	1. Most of the domestic waste contains bio-degradable pollutants.
2. Industrial wastes are produced during industrial and manufacturing processes.	2. Domestic wastes are produced in every home due to day to day activities.
3. Pollution monitoring and controlling bodies like MPCB keep a watch on the proportion of industrial wastes.	3. Pollution monitoring and controlling bodies like MPCB do not keep a watch on the proportion of domestic wastes. It is the individual responsibility of every citizen to reduce the amount of domestic waste that they produce.
4. Fly ash from thermal power plants, heavy metals, chemicals, etc. form the industrial wastes.	4. Garbage, domestic refuse, and discarded solid materials containing food waste, paper, cardboard, peels of fruits, vegetable matter, etc. form the domestic wastes.

Give scientific reasons:

Question 1.
Domestic sewage is harmful for all forms of life.
Answer:

1. Domestic sewage contains water
2. There are detergents and washing private vehicles. powders containing phosphate, which are used to soften the water.
3. These chemicals are harmful to aquatic animals.
4. They also contain disease. causing pathogenic bacteria and viruses.
5. Hence, domestic sewage is harmful for originating from kitchen, bathrooms, toilet, forms of

Question 2.
Use public transport instead of private vehicles.
Answer:

1. All the automobiles use fossil used to soften the water. fuels Burning of fossil fuels causes air pollution by gaseous pollutants as well as by particulates.
2. Toxic gases such as CO, CH₄, SO₂, etc. are emitted through automobile exhausts.
3. When each person uses private vehicles, the proportion of air pollution increases.
4. Instead, public transport helps to reduce air pollution it will also help to ease trafficams.
5. Therefore, as a role of citizen in pollution control, public transport should be used instead of private vehicles.

Question 3.
Due to agriculture, there can be a lot of air pollution.
Answer:

1. During agricultural practices, open field burning is done. Due to this burning there is emission of gases like SO₂, CO₂, CH₄, CO and oxides of nitrogen along with large amounts of particulate matter.
2. In agricultural practices, pesticides used emit toxic chemicals.
3. Industrial farms pollute air by emitting foul odour and airborne pollutants.
4. When manure is decomposed, there is production of greenhouse gases.

Question 4.
A hole has been observed in the ozone layer in the stratosphere near Antarctica.
Answer:

1. Ozone layer depletion is mainly caused due to the action of CFC (Chlorofluorocarbon) molecules in the air.
2. Due to various increased activities of humans, the magnitude of air pollution has been increasing in the last few decades.
3. CFC molecules were used as coolants in refrigerators, freezers and air conditioners.
4. They were also present in industrial solvents, dry cleaning agents and hospital sterilants, aerosols and foam. Due to such enhanced use, much of the CFCs were liberated in the last few years.
5. CFC molecules are decomposed by ultraviolet rays which release chlorine and fluorine molecules.
6. Chlorine and fluorine react with the ozone resulting in a hole in the ozone layer present in the stratosphere.

Therefore, a hole has been observed in the ozone layer in the stratosphere above Antarctica.

Answer the following.

Question 1.
What do you mean by ozone layer depletion? What are the causes of ozone layer depletion?
Answer:
1. The ozone layer is present at the top of the stratosphere. The stratosphere is the second layer of the atmosphere which is present 48 km above the earth’s surface.
2. Ozone layer is protective layer for living organisms of the earth, as it absorbs harmful UV rays from the sun. When this layer is reduced or destroyed, it is called ozone layer depletion.

3. Causes of the ozone layer depletion:

1. The main cause of ozone depletion are CFC molecules.
2. Chlorine atoms are present in chlorofluoro-carbons (CFC) molecules. They react with ozone and deplete it.
3. CFCs are used as coolants in refrigerators, freezers and air conditioners manufactured before 1995.
4. CFCs are also present in industrial solvents, dry cleaning agents and hospital sterilants (sterilizers), aerosols and foam. All the above materials release a lot of CFCs into the atmosphere.
5. CFC molecules are broken down by ultraviolet radiations which result in release of chlorine and fluorine, which further reduce the ozone layer.

Question 2.
What adverse effect does ozone depletion have?
Answer:

1. When the ozone layer is depleted, the ultraviolet radiations of the sun can reach the earth’s surface in greater proportion.
2. This results in damage to animal and plant life on the earth.
3. Ultraviolet rays cause skin cancer and cataract in human beings.
4. The ozone hole is seen in the stratosphere above Antarctica.

Question 3.
Describe the effects of air pollution on animals and plants.
Answer:
1. Effects of air pollution on animals:

• Air pollutants affect breathing of the animals.
• Particulate pollutants can cause problems to the wildlife.
• Particulate matter containing heavy metals is accumulated in the bodies of animals. The accumulated heavy metals at high levels in the body tissues, can cause problems. ‘
• Acid rain causes serious problems to animal life.

2. Effects of air pollution on plants:

• Various parts of the plant show reduced growth after coming in contact with air pollutants.
• The leaves show yellowing or chlorosis on exposure to air pollutants.

Question 4.
What are man-made reasons for water pollution?
Answer:
The effluents and other substances released by man into the surrounding water bodies together can be called man-made reasons for water pollution.
1. Domestic sewage: The excreta, urine and other domestic-use water is added to the water bodies in many cities and villages. In big metro-cities, the sewage is partially treated but these management practices are not enough.

2. Industrial effluent: Different industries and factories release effluents which may contain toxic and harmful components, such as various pigments, bleaching chemicals, leather pieces, fibres, mercury, lead, etc.

3. Oil pollution: Oil spillages are seen in the seas due to leakage of crude oil. The crude oil is hazardous as it contains cancer causing hydrocarbons.

4. Fertilizers and pesticides: These compounds when used in farm, may get washed off to nearby water body. The chemical fertilizer containing N, P, K cause water pollution. Pesticides such as endrin, chlorine, carbonate containing pesticides, etc. are mixed with water. They cause contamination of the aquatic animals.

5. The wrong behaviour of human beings causes water pollution. The addition of wastes, defecation near coasts, washing clothes, decomposing hemp and flax in water, disposal of ashes, floral offerings to god, dumping ashes all such activities result into water pollution.

6. The warm water released into the water body through thermal power plants cause thermal pollution.

Question 5.
What are the effects of water pollution on human beings?
Answer:
The water-borne diseases that are caused by different bacteria and viruses cause infections to human beings through contaminated water. Some bacterial and viral diseases are spread through epidemics. Cholera, hepatitis, enteritis, diarrhoea, typhoid are such diseases that can cause severe infections to man. Polluted water also cause skin diseases and deformities of bones, Some pollutants accumulated in vital organs cause their ailments. Liver, kidneys, brain, etc. are affected in this way. Person may develop hypertension too due to pollutants.

Question 6.
What are the effects of water pollution on the ecosystem?
Answer:
Biological effects:

1. Plants in the ecosystem show retarded growth, resulting into species loss.
2. Due to imbalance in the ecosystem, the food chain and food web is disturbed.
3. Pollutants cause mortality in fish and other aquatic animals.
4. Oil slick causes harmful impact on the marine birds.
5. Useful bacterial fauna in the water is lost.

Abiotic effects:

1. Pollutants cause changes in physical and chemical properties of water.
2. Salinity of the water changes.
3. Dissolved oxygen in the water is depleted, causing mortality of fishes.

Question 7.
Describe the effects of air pollution on the environment.
Answer:
Air pollution can cause the following serious effects on the environment:

1. Deforestation and fuel consumption bring about rise in CO₂ concentration.
2. Excess CO₂ in air causes rise in atmospheric temperature of the earth.
3. The increased temperature is called global warming.
4. The global warming results into melting of glaciers, subsequently causing rise in the sea level.
5. There is a change in the climate and pattern of rainfall. This may indirectly affect the agricultural production.

Question 8.
Describe the effects of soil pollution.
Answer:
Effect of soil pollution:

1. There are many pathogenic bacteria, viruses and parasitic intestinal worms in the sewage sludge. These are able to cause many diseases.
2. Soil and vegetable crops are contaminated by manure made from human and animal excreta containing pathogens. This can lead to various diseases.
3. There is loss of fertility and productivity of soil and land due to soil pollution.
4. Soil pollution leads to water pollution, when toxic chemicals leach into the groundwater. Similarly, when contaminated soil enters into streams or lakes, it also causes water pollution.
5. Radioactive materials and soil contaminants can travel through food chains. They move away from the soil into crops, livestock and human bodies.

Question 9.
How do biodegradable and non- biodegradable wastes cause land pollution?
Answer:

1. Biodegradable material is mainly present in the domestic waste.
2. It is in the form of food waste, peels of fruits, vegetables, etc.
3. Paper is also a main part of the domestic waste which is biodegradable.
4. Polythene bags, plastic waste and footwear, etc. are non-biodegradable waste from the domestic sources. All of these pollute the land.

Question 10.
How do you protect soil from being polluted?
Answer:

1. We should not throw domestic waste and industrial waste indiscriminately on the land, so that it contaminates soil.
2. Proper disposal of solid wastes and more importantly safe disposal of biomedical waste material should be practised.
3. Instead of throwing non-biodegradable materials on the land, they should be properly recycled and reused.
4. Biodegradable materials should be composted and converted into useful manure, rather than throwing them to cause pollution of the soil.
5. Excessive use of fertilizers and pesticides should be avoided so that the soil does not get contaminated.

Question 11.
What are the different laws to prevent pollution?
Answer:
The different laws to prevent pollution are as follows:

1. Water (Prevention and Control of Pollution) Act, 1974.
2. Air (Prevention and Control of Pollution) Act, 1981.
3. Environment (Protection) Act, 1986.
4. There are different laws and rules which have been made for the disposal of hazardous waste, biomedical waste, solid waste and prevention of noise pollution.

Question 12.
Who implements the laws related to pollution?
Answer:
The Central Pollution Control Board (CPCB) and Maharashtra Pollution Control Board (MPCB) check whether the organizations like factories, industrial estates, Municipalities, Zilla Parishads, Panchayat Samities and Gram Panchayats follow all the laws related to control of pollution.

Use your brain power!

Question 1.
Which types of pollutants are observed?
Answer:
Pollutants are of many varied types. They can be classified according to their sources, according to which ecosystem they are polluting, and according to their characteristics.

Question 2.
Whether the pollutants are degradable or non-degradable?
Answer:
Some pollutants are biodegradable while some are non-biodegradable. The pollutants that spread in the air are in the form of gases or particulate matter. Though they are non-degradable, they constantly make chemical reactions with each other.

The pollutants thrown in water and on land are of both the types. Pollutant like plastic is totally non-biodegradable. The biodegradable substances can be decomposed by various bacteria and fungand are converted back into elemental form. The pollutants added in S the water are also of two types. The heavy metals and colours are non-degradable.

Think about it:

Question 1.
If natural materials are pollutants, why do we not perceive their adverse effects during their use? When such materials are referred as pollutants?
Answer:
The natural pollutants are active only for a short duration. Due to natural reasons their activity is limited, and they are lost after a specific time. Their sources are not continuous and their spread too is not regular as in case of man-made pollutants which are emitted steadily.

Thus, we can avoid these substances. We also use them in limited quantity. Therefore, the natural substances, though may be polluting in nature, we are unable to perceive its toxicity. However, if we use them in abundance and create an imbalance, then its effect can be experienced as a great hazard.

Question 2.
What are the reasons other than those mentioned on the textbook page no. 55 mentioned responsible for air pollution?
Answer:
1. The automobile vehicles like two-wheelers and four-wheelers are increasing tremendously in numbers. This uncontrolled number of vehicles and their heavy traffic is causing air pollution to very high level in megacities.
2. Construction industries, demolition of the old buildings, digging the roads, are such activities which are adding to the particulate air pollution of the cities.
3. The bursting of firecrackers on the occasion of festivals and ceremonies, the spread of gulal during processions are also actions which result into unwanted air pollution.
4. Aeroplane traffic, rocket launching, industrial farming are the modern sources of air pollution.

Question 3.
Whether the vehicles with two- stroke engine cause more pollution than four stroke engine?
Answer:
Yes, they do. Scooters and motor cycles are more dominant source of air pollution as they emit soot and organic particles. In urban areas this proportion is high. These particles are toxic and they create heavy air pollution.

The two-wheelers have two-stroke engines. Such engines are far less efficient in burning the fuel that is used in the vehicles. The exhaust systems are also less effective at removing pollutants. On the contrary most of the four-wheelers have catalytic converters. Therefore, the exhaust fumes from scooters contain higher levels of the chemicals found in the fuel and oil they use.

The vehicles with two-stroke engine such as two wheelers emit significantly more primary organic aerosols and volatile organic compounds from incomplete burning of the fuel. They also produce significant secondary organic aerosols as gases released from the exhaust react with the air and microscopic particles of soot.

These pollutants increase the risk of heart and lung disease. Older two-stroke vehicles produced reactive oxygen molecules that are known to be potentially harmful for lung health. In recent times there is excessive use of two-wheelers which is deteriorating the air quality to great extent.

Question 4.
Give 5 examples of each of domestic waste, biological waste and agricultural waste and write in your own words about soil pollution due to those wastes.
Answer:
Domestic waste:

1. Empty containers of medicines, papers, bottles, etc.
2. Plastic
3. Glass pieces
4. Old utensils, clothes
5. Tins and cartons of used items, the discarded household items.

Biological waste:

1. Dead corpse of animals.
2. Urine and faeces
3. Peels of fruits, stalks of vegetables and fruits.
4. Food waste
5. Garlands and old bouquets.

Agricultural waste:

1. The stubs of crops after the grains are removed.
2. Cattle dung and urine
3. Some persistent amount of insecticides
4. Some amount of fertilizers
5. Empty containers, bags, cartons of insecticide, chemical fertilizers, seeds, gunny bags, etc.

Diagram based questions:

Question 1.
Given below is a diagram showing hazardous polluting event.
Explain what is this and what are its effects shown in the diagram.

Answer:
The above picture depicts the formation and effects of acid rain. The toxic gases such as SO2 , CO2 and NO2 are released through the chimneys of factories. These oxides are released in air. They get dissolved in the rainwater and reach back the earth’s surface in the form of acids. The plants, animals and houses are being damaged due to this acid rain.

Question 2.
Draw a well labelled diagram to show greenhouse effect.
Answer:

Activity based questions:

Question 1.
Discuss the issues like ‘dry waste-wet waste’ and ‘toilet in each home’ and write information in your own words.

MCQs based on practical:

Question 1.
Which fertilizers when used in excessive amounts cause soil pollution that spreads to neighbouring water bodies and cause water pollution too?
(a) Chemical
(b) Organic
(c) Artificial
(d) Compost
Answer:
(a) Chemical

Question 2.
What is the type of pollutants that are present in the industrial effluents that is released in the rivers and sea?
(a) Inorganic
(b) Organic
(c) Biological
(d) Biomedical
Answer:
(a) Inorganic

Question 3.
What grows in excess when eutrophication of the water bodies take place?
(a) Plants
(b) Algae
(c) Fishes
(d) Fungi
Answer:
(b) Algae

Question 4.
Which of the following is seen in the polluted water body?
(1) flowers used in pooja
(2) fruits
(3) fishes
(4) aquatic insects
(5) plastic bags
(6) turtles
(7) thick growth of algae
(8) light blue colour of water
(9) cattle wading in water
(10) broken idols
(a) (1) (3) (5) (6) (9) (10)
(b) (1) (2) (5) (7) (9) (10)
(c) (1) (3) (6) (8) (9) (10)
(d) (1) (2) (4) (7) (8) (9)
Answer:
(b) (1) (2) (5) (7) (9) (10)

Question 5.
Which is the easiest method to identify the polluted water?
(a) To taste the water
(b) To check the depth of water
(c) To observe colour and odour of the water
(d) To swim in the water
Answer:
(c) To observe colour and odour of the water

Formative Evaluation:

Question 1.
Which factors are responsible for pollution shown in the following pictures?

Question 2.
Compare the two neighbouring photographs.

Balbharti Maharashtra State Board Class 6 History Solutions Chapter 2 Sources of History Notes, Textbook Exercise Important Questions and Answers.

Maharashtra Board Class 6 History Solutions Chapter 2 Sources of History

Class 6 History Chapter 2 Sources of History Textbook Questions and Answers

1. Answer in one sentence:

Question 1.
In the past, what materials were used for writing?
Answer:
In the past, materials like potsherds, unbaked bricks, bark of birch trees and copper plates were used for writing.

Question 2.
What information is obtained from Vedic literature?
Answer:
We come to know of life of man and ancient Indian History from the Vedic literature.

Question 3.
Which literature is preserved by oral tradition?
Answer:
Owis, folk songs, folk tales and similar literature is preserved by oral tradition.

2. Classify the following sources as material, written and oral sources.
Copper-plate, folk tales, pottery, beads, travelogues, owis, inscriptions, Vedic literature, stupa, coin, Puranas

Material sources	Written sources	Oral sources

Answer:

Material sources	Written sources	Oral sources
pottery	copper-plate	folk tales
beads	travelogues	owis
stupa	inscriptions
coins	vedic literatures
	puranas

3. Observe the picture of earthen pots and try to make similar ones.

4. Observe any coin and note the following things.
Answer:

• Inscription on the coin: Picture of Queen Victoria
• Metal used: Gold
• Year of the coin: 1862
• Symbol on the coin: Queen Victoria
• Picture, language, shape, and denomination of the coin: Queen Victoria, English, round, denomination as per size of the coin.

5. Do you know a few things by heart? Present them in your group

Activity:

Collect pictures /photos of material and written sources and exhibit them.

Class 6 History Chapter 2 Sources of History Additional Important Questions and Answers

Complete the sentence by choosing the correct option:

Question 1.
A number of objects used by our ancestors still _____.
(a) exist
(b) diminish
(c) exhausted
Answer:
exist

Question 2.
______ can also be learnt through customs and traditions, folk arts, folk literature as well as historical documents.
(a) Science
(b) History
(c) Astrology
Answer:
History

Question 3.
______ used by human in the past, provide us with valuable information about life in the ancient times.
(a) Clothes
(b) Cows
(c) Artefacts
Answer:
Artefacts

Question 4.
The ornaments and other artefacts throw light on ______ interaction.
(a) political
(b) social
(c) historical
Answer:
social

Question 5.
We get information about the __________ of the people from the remains of foodgrains, seeds and bones of animals found in excavations.
(a) diet
(b) health
(c) illness
Answer:
diet

Question 6.
Artefacts, articles, monuments or their ruins are called the ______ ‘sources’ of history.
(a) oral
(b) written
(c) material
Answer:
material

Question 7.
The Stone Age people have recorded many events and expressed their _______ in paintings on rocks.
(a) emotions
(b) opinion
(c) views
Answer:
emotions

Question 8.
In the beginning, man wrote on potsherds, unbaked bricks using ________ objects.
(a) blunt
(b) pointed
(c) zigzag
Answer:
pointed

Question 9.
Man began to record the _______ that took place around him.
(a) competitions
(b) points
(c) events
Answer:
events

Question 10.
Many rulers had their orders, judicial decisions, donations, etc., inscribed on stone or _______.
(a) gold-plates
(b) copper-plates
(c) press plates
Answer:
copper-plates

Question 11.
________ means writing sheets made from the bark of a birch tree.
(a) Bhurjapatra
(b) Paper
(c) Book
Answer:
Bhurjapatra

Question 12.
Birch trees are found in _______.
(a) Jammu
(b) Delhi
(c) Kashmir
Answer:
Kashmir

Question 13.
We learn about the Stone Age period of Indian history through _____ excavations.
(a) physical
(b) archaeological
(c) astrological
Answer:
archaeological

Question 14.
In the beginning, the vedas were not in the ________ form.
(a) oral
(b) written
(c) material
Answer:
written

Question 15.
The vedas and the post Vedic literature form an ______ source of ancient Indian History.
(a) important
(b) unimportant
(c) written
Answer:
important

Match the following:

Column (A)	Column (B)
(1) Material (2) Written (3) Oral (4) Pillar inscriptions	(a) Upanishad (b) Folk tales (c) Coins (d) The vedas

Answer:
1 – c
2 – a
3 – b
4 – d

Answer in one sentence:

Question 1.
What are ‘sources of History’?
Answer:
History can be learnt through customs and traditions, folk arts, folk literature as well as historical documents. All these are known as ‘Sources of History’.

Question 2.
How are artefacts useful?
Answer:
Artefacts are useful as they provide us with valuable information about life in the ancient times.

Question 3.
What are artefacts?
Answer:
Things used by man in his day-to-day life are known as artefacts.

Question 4.
What throws light on the social interaction of ancient man?
Answer:
The ornaments and other artefacts throw light on the social interaction of ancient man.

Question 5.
How do we get information about the diet of the ancient people?
Answer:
We get information about the diet of the ancient people from the remains of foodgrains, seeds and bones of animals found in excavation.

Question 6.
What are ‘material sources’ of History?
Answer:
Artefacts, articles, monuments or their ruins are called the ‘material sources’ of history.

Question 7.
What are copper-plates?
Answer:
Copper plates are actual plates made of copper which the rulers used to inscribe their orders, judicial decisions, donations, etc.

Question 8.
What are ‘oral sources’ of history?
Answer:
Owis, folk songs, folk tales and similar literature that is not written but passed on from generation to generation by word of mouth are oral sources of history.

Question 9.
How were vedas preserved before it was put in written form?
Answer:
Before the vedas were written, the ancient Indian had developed the technique of memorizing and reciting them.

Answer the following questions in short:

Question 1.
How did man record events before the art of writing?
Answer:

• The stone age people have recorded many events and expressed their emotions in paintings on rocks
• It was only after thousands of years that man learnt the art of writing.

Question 2.
Write a short note on ‘written sources’ of history.
Answer:

• Man began to record the events that took place around him.
• Over a period of time, many forms of literature developed like books on religious and social subjects, plays, poetry, travelogues and scientific works
• All this literature helps us to understand the history of the various historical periods.
• These sources are known as ‘written sources of history’.

Question 3.
Why should precautions be taken while writing history?
Answer:

• A written document cannot be said to be authentic just because it is old.
• It needs to be examined critically as to who wrote it, why and when it was written
• The conclusions drawn on the basis of various genuine documents have to be cross-checked and corroborated with one another
• Such a critical analysis is very important in the writing of authentic history.

Can you tell?

Structures such as forts, rock-cut caves, stupa etc. are known as material sources of history.
Try to guess what other structures can be called material sources.
Answer:
Coins, potsherd, earthern pot, ornaments or any kind of ancient artefacts can also be called material source.

Balbharti Maharashtra State Board Class 7 Civics Solutions Chapter 3 Features of the Constitution Notes, Textbook Exercise Important Questions and Answers.

Maharashtra Board Class 7 Civics Solutions Chapter 3 Features of the Constitution

Class 7 Civics Chapter 3 Features of the Constitution Textbook Questions and Answers

1. Prepare a table to show the separation of powers in a Federal Government.

Answer:

Union List	State List	Concurrent List
Defence, foreign relations, war and peace, currency, international trade, etc.	Agriculture, law and order, local government, health, prison administration etc.	Employment, environment economic and social planning, personal law, education, etc.

2. Find one word for:

Question 1.
The Government at the centre which carries out the administration of the entire country.
Answer:
Union Government

Question 2.
The machinery with whom rests the responsibility of conducting elections in a free and fair atmosphere.
Answer:
Election Commission.

Question 3.
The third list of subjects for making laws
Answer:
The Concurrent List

3. Answer the following questions.

Question 1.
Why does the Government function at two levels in a Federation?
Answer:
(i) One of the important features of our Constitution is the Federal System.

(ii) In countries with large territories and huge populations, the Government is run by a Federal System.

(iii) Ruling a large territory from a single capital city is not only difficult but may also lead to the neglect of some far-flung areas.

(iv) People residing there cannot participate in the affairs of the Government. Therefore, the governments function at two levels in a § Federation.

Question 2.
What do you understand by Residuaiy Powers?
Answer:
(i) Our Constitution has given three lists on various subjects.

(ii) The first list is called Union List. It contains 97 subjects on which the Union Government makes laws.

(iii) The State List is for the State Governments to legislate upon. It contains 66 subjects.

(iv) Apart from these two lists, there is a Concurrent List which contains 47 subjects.

(v) Both governments can make laws on subjects included in this list. If a subject comes up that is not included in any of the lists, the Union Government is entitled to make laws on it. These powers are termed as ‘Residuary Powers’.

Question 3.
Why has the Constitution created an independent Judiciary in India?
Answer:
(i) The Judiciary of India is independent machinery according to the provisions of the Constitution.

(ii) It is separate from the Executive and Legislative bodies of the Indian Government.

(iii) The Supreme Court is the guardian of the Constitution which ensures that the Fundamental Rights of the citizens are not violated.

(iv) To carry out its duties without fear or favour or external pressure, the Judiciary in India is independent.

4. Hold a group discussion on the merits and demerits of an independent judicial system.
Answer:
Merits of an independent judicial system:

• The judicial system enables the courts to give impartial judgements.
• Judiciary does not act under any political pressure.
• As the judges are appointed by the President and not by the Government.

Demerits of an independent judicial system:

• As the judiciary is independent, it is out of the scope of the government’s control.
• The judiciary is not answerable to anyone if the process of dispensing justice is slow.

5. Find out about the Electronic Voting Machine (EVM) and discuss the advantages of conducting elections with EVM.
Answer:

• Difficult to tamper/cheat
• Cost-effective and economical
• Time-saving
• Calculation is faster
• Easy to use / carry / transport
• Data can be saved for later use.

Activity:

Establish an Election Commission in your class, decide upon the positions you would like to fill through elections. Then conduct elections under the guidance of this Commission.

Class 7 Civics Chapter 3 Features of the Constitution InText Questions and Answers

Do this:

Question 1.
Make a list of North-Eastern Indian States and name their capital cities.
Answer:

State	Capital
Arunachal Pradesh	Itanagar
Assam	Dispur
Meghalaya	Shillong
Manipur	Imphal
Mizoram	Aizwal
Nagaland	Kohima
Tripura	Agartala

Find out:

Question 1.
Find out about the Electronic Voting Machine (EVM) and discuss the advantages of conducting elections with EVM.
Answer:

• Difficult to tamper/cheat
• Cost effective and economical
• Time saving
• Calculation is faster
• Easy to use / carry / transport
• Data can be saved for later use.

Question 2.
How many amendments have been made in the Indian Constitution till date?
Answer:
As of September 2016, there have been 101 (latest of List Bill) amendments to the Constitution of India, since it was first enacted in 1950.

Class 7 Civics Chapter 3 Features of the Constitution Additional Important Questions and Answers

Complete the sentence by choosing the appropriate words from the options given below:

Question 1.
One of the important features of our Constitution is the _______ System. (Federal, Unitary, Republic)
Answer:
Federal

Question 2.
The Government functions at ________ levels in a Federation. (two, three, four)
Answer:
two

Question 3.
The Government that oversees the administration of the region that we live in is called _______.(Union Government, State Government, None of the above)
Answer:
State Government

Question 4.
The system of running the administration of a country cooperatively by the governments at two levels, making laws about different subjects is called __________. (Socialism, Communism, Federalism)
Answer:
Federalism

Question 5.
The ______ is for the Union Government to make laws. (State List, Union List, Concurrent List)
Answer:
Federalism

Question 6.
The _______ is for the State Government to legislate upon. (Union List, State List, Concurrent List)
Answer:
State List

Question 7.
The ______ List contains 47 subjects and both the Government can make laws on these subjects. (Concurrent List, Union List, State List)
Answer:
Concurrent List

Question 8.
If a subject comes up and it is not included in any of the Lists, the _______ is entitled to make laws. (State Government, Union Government, President)
Answer:
Union Government

Question 9.
In India, there are ____ State Governments and _______ Union Territories.(29, 7 ; 28, 8)
Answer:
29, 7

Question 10.
The ______ System of Government the Legislature has the highest decision making power. (Parliamentary, Autocratic, Communist)
Answer:
Parliamentary

Question 11.
The ______ who runs the administration emerge from the Lok Sabha and is / are answerable to the Lok Sabha for all its / their decisions.
(Opposition Ministers, Council of Ministers,President)
Answer:
Council of Ministers

Question 12.
Judges are appointed by the ______ (President, Government, Vice-President)
Answer:
President

Question 13.
The Indian Constitution has granted _________ to all Indians. (Single citizenship, Dual citizenship, None of these)
Answer:
Single citizenship

Question 14.
The ________ ensures free, fair and just atmosphere for the election. (President, Election Commission, Ruling Party)
Answer:
Election Commission.

Match the following:

Question 1.

Column ‘A’	Column ‘B’
(1) War and peace (2) Law and order (3) Economic and Social planning	(a)  State Government (b) Both Union and State Government (c) Union Government

Answer:
1 – c
2 – a
3 – b

State whether the following statements are true or false with reasons:

Question 1.
Defence is a subject on which the State Government makes laws.
Answer:
False:

• The Constitution has divided the subjects for making laws between the Union and the State Government.
• Defence is a subject on which Union Government makes laws.

Question 2.
The Union List contains 97 subjects and defence is one of the subjects included in it.
Answer:
True.

Question 3.
Chandigarh is controlled by the State Government.
Answer:
False: Chandigarh is one of the seven Union Territories of India. The Union Government controls the Union Territories.

Question 4.
In India, the Executive has the highest decision-making power.
Answer:
False: The Indian Constitution has provided for a Parliamentary System of Government. In such a system the Parliament, i.e. the Legislature has the highest decision-making power.

Name the following:

Question 1.
The system which is an important feature of our Constitution.
Answer:
Federalism

Question 2.
The Government that oversees the administration of the place we live.
Answer:
State Government

Question 3.
Number of subjects in the Union List on which the Union Government makes laws.
Answer:
97 Subjects

Question 4.
The list with 66 subjects which the State government legislates upon.
Answer:
The State List

Question 5.
The powers of the Union Government to make laws on a subject which comes up and is not mentioned in any list.
Answer:
Residuary Powers

Question 6.
Any two subjects with the Union Government.
Answer:
Defence, Currency

Question 7.
Subjects with the State Government
Answer:
Health, Prison

Question 8.
Subjects with both the governments.
Answer:
Employment, Education

Question 9.
2 Union Territories in India.
Answer:
Daman and Diu, New Delhi

Question 10.
Answerable to the Lok Sabha
Answer:
The Council of Ministers.

Question 11.
An example to show that the Indian Judiciary is independent.
Answer:
Appointment of Judges by the President

Question 12.
The type of citizenship granted to the citizens by the Indian Constitution.
Answer:
Single citizenship

Answer in one or two sentences:

Question 1.
Write any one of the important features of our Constitution.
Answer:
Federal system is one of the important features of our Constitution.

Question 2.
In which countries are governments run by the Federal System?
Answer:
In countries with large territories and huge population, the Government is run by a Federal System.

Question 3.
What is the problem faced while ruling a large territory from a single capital?
Answer:
Ruling a large territory from a single capital city is not only difficult but may also lead to neglect of some far-flung areas.

Question 4.
Explain the term Union Government.
Answer:
The Government at the centre carries out tasks like defence of the entire country, foreign policy, establishing peace, etc. It is called ‘Union Government or ‘Federal Government’.

Question 5.
What do you mean by State Government?
Answer:
The Government that oversees the administration of the region that we live in is called State Government.

Question 6.
What is called ‘Federalism’?
Answer:
The system of running the administration of a country cooperatively by the Governments at two levels, making laws about different subjects is called ‘Federalism’.

Question 7.
Which are the three lists into which the Constitution has divided subjects for making Laws?
Answer:
The three lists into which the Constitution has divided subjects for making laws are State List, Union List and Concurrent List.

Question 8.
Which powers are termed as Residuary Powers?
Answer:
(a) If a subject comes up that is not included in any of the three Lists, the Union List, the State List or the Concurrent List, the Union Government is entitled to make laws on it
(b) These powers are termed as residuary powers.

Question 9.
Which are the seven Union territories in India?
Answer:
The seven Union Territories in India are New Delhi, Daman and Diu, Puducherry, Chandigarh, Dadra and Nagar Haveli, Andaman and Nicobar Islands and Lakshadweep.

Question 10.
In the Parliamentary system of Government, who has the highest decision-making power?
Answer:
In the Parliamentary system of Government, the Parliament has the highest decision-making power.

Question 11.
What does the Indian Parliament include?
Answer:
The Indian Parliament includes the President, the Lbk Sabha or the House of the People and the Rajya Sabha or the Council of States.

Question 12.
Whom is the Council of Ministers answerable to, for all its decisions?
Answer:
The Council of Ministers is answerable to the Lok Sabha for all its decisions.

Question 13.
What have great significance in Parliamentary Democracy?
Answer:
In Parliamentary Democracy, the discussion and debates that take place in the Parliament have great significance.

Question 14.
Which disputes are referred to the Judiciary?
Answer:
The disputes that cannot be resolved mutually are referred to the Judiciary.

Question 15.
Which are the two provisions in the Constitution which ensures that the Judiciary remains more independent?
Answer:
The two provisions in the Constitution which ensures independence of Judiciary are that the judges are appointed by the President and not by the Government, and it is not easy to remove the Judges from their office.

Question 16.
Why is it necessary to amend the Constitution?
Answer:
There comes up a need to make changes or amendments in the provisions of the Constitution due to the changing circumstances.

Question 17.
What can frequent amendments in the Constitution lead to?
Answer:
Frequent amendments in the Constitution may lead to instability.

Question 18.
Write a short note on Parliamentary System of Government.
Answer:
(i) The Indian Constitution has provided for a Parliamentary System of Government.

(ii) In such a system, the Parliament, i.e. the Legislature has the highest decision-making power.

(iii) The Indian Parliament includes the President, the Lok Sabha or the House of the People and the Rajya Sabha or the Council of States.

(iv) The Council of Ministers that run the administration emerge from the Lok Sabha and is answerable to the Lok Sabha for all its decisions. In Parliamentary Democracy, the discussion and debates that take place in the Parliament have great significance.

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 13 Chemical Change and Chemical Bond Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 8 Science Solutions Chapter 13 Chemical Change and Chemical Bond

Class 8 Science Chapter 13 Chemical Change and Chemical Bond Textbook Questions and Answers

1. Complete the statement by filling the gaps using appropriate term from the terms given in the brackets:
(slow, coloured, arrow, fast, smell, milky, physical, product, chemical, reactant, covalent, ionic, octet, duplet, exchange, sharing, equality sign)

Question a.
An ……….. is drawn in between the reactants and products while writing the equation for a chemical reaction.
Answer:
An arrow is drawn in between the reactants and products while writing the equation for a chemical reaction.

Question b.
Rusting of iron is a ……….. chemical change.
Answer:
Rusting of iron is a slow chemical change.

Question c.
The spoiling of food is a chemical change which is recognized from the generation of certain …………. due to it.
Answer:
The spoiling of food is a chemical change which is recognized from the generation of certain smell due to it.

Question d.
A colourless solution of calcium hydroxide in a test tube turns ………….. on blowing in it through a blow tube for some time.
Answer:
A colourless solution of calcium hydroxide in a test tube turns milky on blowing in it through a blow tube for some time.

Question e.
The white particles of baking soda disappear when put in lemon juice. This means that it is a ……….. change.
Answer:
The white particles of baking soda disappear when put in lemon juice. This means that it is a chemical change.

Question f.
Oxygen is a …………….. in respiration.
Answer:
Oxygen is a reactant in respiration.

Question g.
Sodium chloride is …………… compound while hydrogen chloride is compound.
Answer:
Sodium chloride is ionic compound while hydrogen chloride is covalent compound.

Question h.
Electron …………….. is complete in each hydrogen in a hydrogen molecule.
Answer:
Electron duplet is complete in each hydrogen in a hydrogen molecule.

Question i.
Chlorine (Cl₂) molecule is formed by ………….. of electrons between two chlorine atoms.
Answer:
Chlorine (Cl₂) molecule is formed by sharing of electrons between two chlorine atoms.

2. Explain by writing a word equation. 

Question a.
Respiration is a chemical change.
Answer:
Respiration is a biological process, in this process air is inhaled, oxygen present in this inhaled air reacts with glucose present in the cells of the body forming carbon dioxide and water. Moreover, we cannot obtain glucose and oxygen from carbon dioxide and water. Hence, respiration is a chemical change.
Word equation:

Question b.
Hard water gets softened on mixing with a solution of washing soda.
Answer:
Hard water does not form lather with soap and is brackish to taste. This is because hard water contains the chloride and sulphate salts of calcium and magnesium in dissolved state. When a solution of washing soda is added to hard water, it forms a precipitate of calcium carbonate and magnesium carbonate, which is removed by filtration thus water is softened.
Word equation:

Question c.
Limestone powder disappears on adding to dilute hydrochloric acids.
Answer:
In the reaction of dil. HCl and limestone powder (CaCO₃), limestone disappears slowly and carbon dioxide (CO₂) liberates slowly.
Word equation:

Question d.
Bubbles are seen on adding lemon juice to baking soda.
Answer:
When baking soda is added to lemon juice a chemical change takes place in citric acid present in the lemon juice and carbon dioxide gas is formed. Word equation:

This is a neutralization reaction.

3. Match the pairs.

Question a.

Column I	Column II
1. Photosynthesis	a. Tendency to lose electrons
2. Water	b. Reactant in combustion process
3. Sodium chloride	c. Chemical change
4. Dissolution of salt in water	d. Covalent bond
5. Carbon	e. Ionic bond
6. Fluorine	f. Physical change
7. Magnesium	g. Tendency to form anion

Answer:

Column I	Column II
1. Photosynthesis	c. Chemical change
2. Water	d. Covalent bond
3. Sodium chloride	e. Ionic bond
4. Dissolution of salt in water	f. Physical change
5. Carbon	b. Reactant in combustion process
6. Fluorine	g. Tendency to form anion
7. Magnesium	a. Tendency to lose electrons

4. Show with the help of diagram of electronic configuration how the following compounds are formed from the constituent atoms.

Question a.
Sodium Chloride:

Answer:
1. Sodium has atomic number 11 and electronic configuration 2, 8, 1.
2. Sodium atom has 1 electron in its outermost shell.

3. It loses one electron from its outermost shell, i.e., M shell. Then its L shell becomes the outermost shell with a stable octet. The nucleus of sodium atom has 11 protons but the number of electrons in the atom has become 10. So, there is a net unit positive charge giving a sodium cation (Na⁺).

4. On the other hand, chlorine has electronic configuration 2, 8, 7. Chlorine atom has 7 electrons in its outermost shell and requires one electron to complete its octet.
5. Thus, the electron lost by sodium is taken up by chlorine.

6. When chlorine atom gains one electron, octet of chlorine is completed and its K, L, M shells have together 18 electrons and the nucleus has 17 protons. This leads to the formation of an ion (CP).

7. Thus, a chlorine atom accepts one electron from a sodium atom and consequently a chloride ion with one unit negative charge and a sodium ion with one unit positive charge are formed.

8. Sodium and chloride ions, being oppositely charged, attract each other due to the electrostatic force of attraction. An ionic bond is formed and this results in the formation of sodium chloride (NaCl) molecule.

Question b.
Potassium fluoride:
Answer:
1. Potassium has atomic number 19 and electronic configuration 2, 8, 8, 1.
2. Potassium atom has 1 electron in its outermost shell.

3. It loses one electron from its outermost shell, i.e. N shell. Then its M shell becomes the outermost shell with a stable octet. The nucleus of potassium atom has 19 protons but the number of electrons in the atom has become 18. So there is a net unit positive charge giving a potassium cation (K⁺).

4. On the other hand, fluorine has electronic configuration 2, 7. Fluorine has 7 electrons in the outermost shell and requires one electron to complete its octet.

5. Thus, the electron lost by potassium is taken up by chlorine.

6. When fluorine atom gains one electron, octet of fluorine is completed, its K and L shells have together 10 electrons and the nucleus has 9 protons. This leads to the formation of an ion (F^–).

7. Thus, a fluorine atom accepts one electron from a potassium atom and consequently a fluoride ion with one unit negative charge and a potassium ion with one unit positive charge are formed.

8. Potassium and fluoride ions, being oppositely charged, attract each other due to electrostatic force of attraction. An ionic bond is formed and this results in the formation of potassium fluoride (KF) molecule.

Question c.
Water:
Answer:

1. Hydrogen has atomic number 1 and electronic configuration 1.
2. Hydrogen has 1 electron in its K shell.

3. Oxygen has atomic 8 and electronic configuration 2, 6. There are 6 electrons in the valence shell of oxygen atom. It means that the electron octet in oxygen is short of two electrons and the valency of oxygen is two.

4. In the H₂O molecule, the oxygen atom complete its octet by sharing two electrons one each with two hydrogen atoms, thus, forming two covalent bonds. While this happens, the duplets of two hydrogen atoms are completed.

Question d.
Hydrogen chloride:
Answer:
1. Hydrogen has atomic number 1 and electronic configuration 1, that means it has 1 electron in its K shell and its duplet is short of one electron therefore, the valency of hydrogen is one.

2. On the other hand, chlorine has electronic configuration 2, 8, 7. Chlorine atom has 7 electrons in its outermost shell and requires one electron to complete its octet.

3. The two atoms, hydrogen and chlorine share one electron with each other. As a result, the electron duplet of hydrogen and octet of chlorine is complete and a covalent band is formed between them.

Can you recall?

Question a.
What are the methods of classification of changes?
Answer:
The methods of classification of changes: Physical change and chemical change.

Question b.
What is the difference between physical and chemical change?
Answer:

1. In physical change, the composition of substance does not change. No new substance is formed.
2. In chemical change, the composition of compounds change and new compounds are formed.

Question c.
Classify the following changes into physical and chemical change. Ripening of mango, melting of ice, boiling of water, dissolution of salt in water, Ripening of banana, fragrance on ripening fruit, darkening of a cut potato, bursting of an inflated balloon, sound of bursting fire cracker, foul smell from a portion of spoiled food.
Answer:

• Physical change: Melting of ice, boiling of water, dissolution of salt in water.
• Chemical change: Ripening of mango, ripening of banana, fragrance of ripening fruit, darkening of a cut potato, bursting of an inflated balloon, sound of bursting firecracker, foul smell from a spoiled food.

Project:

Question a.
Prepare a list of the chemical changes that occur in your house and surroundings and discuss these in the class.

Class 8 Science Chapter 13 Chemical Change and Chemical Bond Important Questions and Answers

Fill in the blanks:

Question 1.
……………. is a continuously occurring biological process.
Answer:
Respiration is a continuously occurring biological process.

Question 2.
The reaction between citric acid and sodium bicarbonate is a ……………. reaction.
Answer:
The reaction between citric acid and sodium bicarbonate is a neutralization reaction.

Question 3.
Combustion of fuel is a ………… and ……………. chemical change.
Answer:
Combustion of fuel is a fast and irreversible chemical change.

Question 4
Electronic configuration of sodium is …………….
Answer:
Electronic configuration of sodium is 2, 8, 1.

Question 5.
Electronic configuration of chlorine is …………….
Answer:
Electronic configuration of chlorine is 2, 8, 7.

Question 6.
A chemical bond formed by sharing of valence electrons of two atoms with each other is called a …………….
Answer:
A chemical bond formed by sharing of valence electrons of two atoms with each other is called a covalent bond.

Question 7.
Hard water contains the chloride and sulphate salts of ……………. and ……………. in dissolved state.
Answer:
Hard water contains the chloride and sulphate salts of calcium and magnesium in dissolved state.

Question 8.
Electronic configuration of fluorine is …………….
Answer:
Electronic configuration of fluorine is 2, 7.

Question 9.
Green plants perform ……………. in sunlight.
Answer:
Green plants perform photosynthesis in sunlight.

Question 10.
Melting of ice is a ……………. change.
Answer:
Melting of ice is a physical change.

Question 11.
The chloride ion has a ……………. charge.
Answer:
The chloride ion has a negative charge.

Question 12.
A covalent bond between two atoms is also represented by ……………. joining their symbols.
Answer:
A covalent bond between two atoms is also represented by dash joining their symbols.

Rewrite the following statements by selecting the correct options:

Question 1.
Sodium atoms and sodium ions ………….. .
(a) are chemically the same
(b) have the same number of protons
(c) have the same number of electrons
(d) form covalent bond
Answer:
(b) have the same number of protons

Question 2.
An ionic bond is formed when …………….. .
(a) two metallic elements react
(b) two nonmetallic elements react
(c) a metallic element reacts with a non-metallic element
(d) a pair of elements react
Answer:
(c) a metallic element reacts with a non-metallic element

Question 3.
…………….. tries to establish the duplet state in its outermost orbit by sharing electrons.
(a) Sodium
(b) Potassium
(c) Hydrogen
(d) Magnesium
Answer:
(c) Hydrogen

Question 4.
…………… is an electron donor.
(a) Helium
(b) Iodine
(c) Chlorine
(d) Magnesium
Answer:
(d) Magnesium

Question 5.
………………. combine to form an ionic compound.
(a) Hydrogen and chlorine
(b) Hydrogen and oxygen
(c) Potassium and chlorine
(d) Nitrogen and oxygen
Answer:
(c) Potassium and chlorine

Question 6.
……………. is an example of chemical change.
(a) Magnetism of iron
(b) Rusting of iron
(c) Heating of iron till it becomes red hot
(d) Dissolution of salt in water
Answer:
(b) Rusting of iron.

State whether the following statements are True or False. (If a statement is false, correct it and rewrite it.)

Question 1.
The preparation of cold drink soda- lemon is a physical change.
Answer:
False. [The preparation of cold drink soda-lemon is a chemical change.]

Question 2.
Hard water contains the chloride and sulphate salts of calcium and magnesium in dissolved state.
Answer:
True.

Question 3.
Combustion of fuel is a fast and irreversible man-made chemical change.
Answer:
True.

Question 4.
Photosynthesis reaction is a man-made chemical change.
Answer:
False. [Photosynthesis reaction is a natural chemical change.]

Question 5.
The atoms with incomplete electron octet/duplet form chemical bonds.
Answer:
True.

Question 6.
Electronic configuration of chlorine is 2, 8, 6.
Answer:
False. (Electronic configuration of chlorine is 2, 8, 7.)

Question 7.
One ionic bond is formed due to the electrical change +1 or -1 on an ion.
Answer:
True.

Question 8.
H₂O Molecule is an ionic compound.
Answer:
False. (H₂O molecule is a covalent compound.)

Question 9.
The bond between two chlorine atoms is a covalent band.
Answer:
True.

Question 10.
Arrow indicates the direction of the reaction.
Answer:
True.

Consider the correlation between the words of the first pair, match the third word/words with the most appropriate answer:

Question 1.
K : 2, 8, 8, 1 : : Mg : ………………
Answer:
2, 8, 2

Question 2.
MgCl₂ : Ionic bond : : CaO : ……………..
Answer:
Covalent bond

Question 3.
Photosynthesis : Natural chemical change : : Cold drink, soda lemon : ………
Answer:
Man-made chemical change

Question 4.
Respiration: Glucose + Oxygen : : Neutralization : ………….
Answer:
Acid + alkali.

Match the columns:

Question 1.

Column I	Column II
1. Respiration	a. Potassium and fluorine
2. Acid + Base	b. Glucose and oxygen
3. Photosynthesis	c. Carbon dioxide and water
4. Ionic bond	d. Salt and water

Answer:

Column I	Column II
1. Respiration	c. Carbon dioxide and water
2. Acid + Base	d. Salt and water
3. Photosynthesis	b. Glucose and oxygen
4. Ionic bond	a. Potassium and fluorine

Define the following:

• Chemical change: In a chemical change, the chemical composition of the original matter changes and new substances having different properties and different chemical composition are formed.
• Ionic bond: The chemical bond formed due to an electrostatic force of attraction between the oppositely charged cation and anion is called an ionic bond or an electrovalent bond.
• Covalent bond: The chemical bond formed by sharing of valence electrons of two atoms with each other is called a covalent bond.

Answer the following questions in one sentence each:

Question 1.
Name the reactants in respiration.
Answer:
Glucose and oxygen are the reactants in respiration.

Question 2.
Name the products of respiration.
Answer:
Carbon dioxide and water are the products of respiration.

Question 3.
Name the reactants in photosynthesis.
Answer:
Carbon dioxide and water are the reactants in photosynthesis.

Question 4.
Name the products of photosynthesis.
Answer:
Glucose and oxygen are the products of photosynthesis.

Question 5.
Name the salts present in hard water.
Answer:
Salts present in hard water are calcium chloride, magnesium chloride, calcium sulphate and magnesium sulphate.

Question 6.
Give two examples of ionic compounds.
Answer:
Ionic compounds: Sodium chloride (NaCl), Potassium fluoride (KF).

Question 7.
Give two examples of covalent compounds.
Answer:
Covalent compounds: Hydrogen (H₂), Water (H₂O).

Question 8.
Name an acid used for cleaning Shahabad tile.
Answer:
An acid used for cleaning Shahabad tile is dilute hydrochloric acid (HCl).

Question 9.
Write a chemical equation for combustion of fuel.
Answer:
Chemical equation:
C + O₂ → CO₂

Question 10.
Write a chemical equation for photosynthesis.
Answer:
Chemical equation:

Answer the following questions:

1. Explain by writing a word equation.

Question 1.
Combustion of fuel is a fast and irreversible chemical change.
Answer:
Wood, coal, petrol or cooking gas are burnt for producing energy. Carbon is the common substance that burns in all these fuels. The product carbon dioxide is formed when carbon combines with oxygen in the air during the combustion process. We cannot obtain fuel from carbon dioxide by employing any other method. Properties of carbon dioxide are altogether different from those of fuel. Hence, this change is a irreversible chemical change.
Word equation:
Carbon + Oxygen → Carbon dioxide

Question 2.
Dilute hydrochloric acid is used for cleaning Shahabad tiles.
Answer:
The main constituent of Shahabad tile is calcium carbonate. During its cleaning with hydrochloric acid, the upper layer of the tile reacts with hydrochloric acid and three products are formed. One of them is calcium chloride, which being soluble in water, gets washed away with water. The second product is carbon dioxide, it mixes with air. The third product is water.
Word equation:

2. Write a chemical equation (unbalanced) for the following reactions:

Question 1.

Answer:
Chemical equation:
CO₂ + Ca(OH)₂ → CaCO₃ + H₂O

Question 2.

Answer:
Chemical equation:
CaCO₃ + HCl → CaCl₂ + CO₂ + H₂O

Question 3.
Magnesium salts during the softening of hard water.

Answer:
Chemical equation:
MgCl₂ + Na2CO₃ → MgCOg + 2NaCl

3. Show with the help of diagram of electronic configuration how the following compounds are formed from the constituent atoms.

Question 1.
Hydrogen molecule:
Answer:
1. Hydrogen has atomic number 1 and electronic configuration 1. That means it has 1 electron in its K shell and its duplet is short of one electron therefore, the valency of hydrogen is one.

2. The two atoms of hydrogen are identical, they share their electrons with each other.
3. As a result, the electron duplet of both the hydrogen atoms is complete and a covalent band is formed between them.

4. There is one covalent bond between the component atoms H and Cl of the molecule HCl. Use this information to represent the formation of HCl molecules from H and Cl atoms diagrammatically.
(Use your brainpower)
Answer:
Hydrogen chloride:
1. Hydrogen has atomic number 1 and electronic configuration 1, that means it has 1 electron in its K shell and its duplet is short of one electron therefore, the valency of hydrogen is one.

2. On the other hand, chlorine has electronic configuration 2, 8, 7. Chlorine atom has 7 electrons in its outermost shell and requires one electron to complete its octet.

3. The two atoms, hydrogen and chlorine share one electron with each other. As a result, the electron duplet of hydrogen and octet of chlorine is complete and a covalent band is formed between them.

5. Show the formation of the following ionic compounds from the corresponding elements using two methods namely, numerical and diagrammatic representation of electronic configuration.
(a) K⁺ F^–, from 19K and 9F, (b) Ca²⁺ O^2- from ₂₀Ca and ₈O.
(Use your brainpower)
Answer:
(a) K⁺F^– from ₁₉K and ₉F
Potassium fluoride:
1. Potassium has atomic number 19 and electronic configuration 2, 8, 8, 1.
2. Potassium atom has 1 electron in its outermost shell.

3. It loses one electron from its outermost shell, i.e. N shell. Then its M shell becomes the outermost shell with a stable octet. The nucleus of potassium atom has 19 protons but the number of electrons in the atom has become 18. So there is a net unit positive charge giving a potassium cation (K⁺).

4. On the other hand, fluorine has electronic configuration 2, 7. Fluorine has 7 electrons in the outermost shell and requires one electron to complete its octet.

5. Thus, the electron lost by potassium is taken up by chlorine.

6. When fluorine atom gains one electron, octet of fluorine is completed, its K and L shells have together 10 electrons and the nucleus has 9 protons. This leads to the formation of an ion (F^–).

7. Thus, a fluorine atom accepts one electron from a potassium atom and consequently a fluoride ion with one unit negative charge and a potassium ion with one unit positive charge are formed.

8. Potassium and fluoride ions, being oppositely charged, attract each other due to electrostatic force of attraction. An ionic bond is formed and this results in the formation of potassium fluoride (KF) molecule.

(b) Ca²⁺O^2- from ₂₀Ca and ₈O.

Distinguish between the following:

Question 1.
Physical change and Chemical change:
Answer:

Physical change	Chemical change
1. In this change, the composition of the substance does not change. No new substance is formed.	1. In this change, the composition of the compounds change and new compounds are formed.
2. In this case, physical properties such as state, colour, density, etc. are changed.	2. In this case, physical and chemical properties are entirely changed.
3. This change is temporary.	3. This change is permanent.
4. In this case, the original substance can be recovered by simple means or by merely reversing the process.	4. In this case, the original substance cannot be recovered by easy means or by reversing the process.

Question 2.
Ionic bond and Covalent bond:
Answer:

Ionic bond	Covalent bond
1.  Ionic bond is formed due to the transfer of electrons from one atom to another.	1. Covalent bond is formed due to the sharing of electrons between two or more atoms.
2. Atoms of metals and nonmetals combine to form ionic bonds.	2. Atoms of nonmetals combine to form covalent bonds.
3. Molecules of the compounds formed due to ionic bond split up into ions in aqueous solution.	3. Molecules of the compounds formed due to covalent bond so not split up into ions in a solution.

Give scientific reasons:

Question 1.
Ionic compounds are formed due to the combination of metallic and nonmetallic atoms.
Answer:
Metallic atoms have a tendency to lose electrons from their outermost orbits to establish the octet state in their penultimate orbits. Conversely, nonmetallic atoms gain electrons to establish the octet state of their outermost orbits.

When a metallic atom and a nonmetallic atom come close together, the metallic atom loses electrons and gets c converted into positively charged ion, while the nonmetallic’ atom gets converted into negatively charged ions so formed, develop an ionic bond and this results in the formation of an ionic compound. Hence, ionic compounds are formed due to the combination of metallic and nonmetallic atoms.

Activity-based questions:

Activity 1:

Take the lemon juice in a clean glass. Take two drops of the lemon juice in a spoon and taste. Add a pinch of baking soda in the glass of lemon juice. Did you notice bubbling around the particles of soda? Did you hear a sound on taking your ear near the glass? Now again taste it. Did it taste as sour as it was in the beginning? (Above activity is to be done using clean apparatus and edible material. Then only it is possible to test the ’taste’, otherwise keep in mind that the testing of ‘taste’ cannot be done.)

Activity 2:
Take some freshly prepared lime water (solution of calcium hydroxide) in a test tube. Keep on blowing in it with a blow tube. What is seen after some time? Did the colourless lime water turn milky? After some more time you will find that a white insoluble solid settles at the bottom of the test tube. This is a precipitate of calcium carbonate. The turning lime water milky means that the blown gas mixed in it was carbon dioxide.

Write a chemical equation for the above word equation.
Chemical equation:
CO₂ + Ca(OH)₂ → CaCO₃ + H₂O

Balbharti Maharashtra State Board Class 6 History Solutions Chapter 1 The Indian Subcontinent and History Notes, Textbook Exercise Important Questions and Answers.

Maharashtra Board Class 6 History Solutions Chapter 1 The Indian Subcontinent and History

Class 6 History Chapter 1 The Indian Subcontinent and History Textbook Questions and Answers

1. Answer the following in one sentence:

Question 1.
What is history?
Answer:
History is a coherent account of the significant past events in the progress of human culture.

Question 2.
Where do human settlements flourish?
Answer:
Human settlements have flourished wherever the means of living are plentiful.

Question 3.
What do the people in the hilly region j depend on for their food?
Answer:
In the hilly regions people depend more on hunting and gathering for their food.

Question 4.
Which was the earliest civilization in India?
Answer:
The Harappan civilization was the earliest civilization in India.

2. Answer the following questions in short:

Question 1.
What does human life depend on?
Answer:
Human life in any region depends to a large extent on its geographical characteristics, diet, clothing, housing and occupation.

Question 2.
What features of our surroundings form the means of our livelihood?
Answer:
The climate, rainfall, agricultural produce, flora and fauna of the region where we live form the source or means of our livelihood.

Question 3.
Which region is known as the Indian subcontinent?
Answer:
Afghanistan, Pakistan, Nepal, Bhutan, Bangladesh, Sri Lanka and India together form the region known as south Asia. Considering the expanse and significance of India in this region, it is also known as the Indian subcontinent.

3. Give reasons:

Question 1.
There is a close relation between history and geography.
Answer:

• Time, place, society and individuals are four major pillars without which history cannot be written.
• Of these four components ‘place’ is related to geography or geographical conditions.
• This makes history and geography inseperable i.e. very closely related.

Question 2.
People are forced to leave their settlements.
Answer:

• Sometimes reasons like degradation of the environment, drought, invasion, etc. leads to scarcity of means.
• Therefore, people are forced to leave their settlements in their fight for survival.

4. Explain the difference in the human life in the hilly regions and that on the plains.
Answer:

Human life in the Hilly region	Human life in the Plains
(1) Human life was very strenuous	(1) Life was more comfortable.
(2) Land was not fertile. therefore no So agriculture was wcarried on.	(2) Land was very Fertile So agriculture   was carried on.
(3) Grains and vegetables Grains and are scarce.	(3) Grains and vegetables are found in plenty
(4) They depend on hunting and gathering  for their food.	(4) They do not depend on hunting and gathering for their food.

5. Observe the physical map of India and answer the questions based on it:

Question 1.
Which mountain ranges lie in the north of India?
Answer:
The Hindukush and the Himalayan mountain ranges.

Question 2.
Which are the routes to India from the north-east?
Answer:
The route to India from the north east is by sea.

Question 3.
Where do the Ganga and Brahmaputra meet?
Answer:
The Ganga and Brahmaputra meet in Bangladesh.

Question 4.
Name the islands to the east of the Indian peninsula.
Answer:
The Andaman and Nicobar islands are the Indian islands to the east of the Indian peninsula.

Question 5.
In which part of India do we see the Thar Desert?
Answer:
We see the Thar Desert in the north western part of India.

Activity:

• Obtain information about the lakes or reservoirs in your locality.
• Show the following on a world map :
  1. The Himalaya Mountain
  2. The Silk Road
  3. Arabia

Class 6 History Chapter 1 The Indian Subcontinent and History Additional Important Questions and Answers

Complete the sentence by choosing the correct option:

Question 1.
________ is a coherent account of the significant past events in the progress of human culture.
(a) History
(b) Geography
(c) Civics
Answer:
History

Question 2.
Not much fertile land is available in the ______ region.
(a) plains
(b) hilly
(c) plateau
Answer:
hilly

Question 3.
Grains and vegetables are _______ in the hilly areas.
(a) scarce
(b) plenty
(c) moderate
Answer:
scarce

Question 4.
In the ______ regions, people depend more on hunting and gathering for their food.
(a) plateau
(b) plains
(c) hilly
Answer:
hilly

Question 5.
Human settlements have flourished wherever the means of living are _______.
(a) scarce
(b) plentiful
(c) moderate
Answer:
plentiful

Question 6.
_____ lies to the north of India.
(a) Andaman
(b) Western Ghats
(c) Himalayas
Answer:
Himalayas

Question 7.
_____ lies to the east of India.
(a) Bay of Bengal
(b) Eastern ghats
(c) Lakshadweep
Answer:
Bay of Bengal

Question 8.
_________ lies to west of India.
(a) Himalayas
(b) Arabian sea
(c) Brahmaputra
Answer:
Arabian sea

Question 9.
______ lies to the south of India.
(a) Indian Ocean
(b) Arabian Sea
(c) Pacific Ocean
Answer:
Indian Ocean

Question 10.
The Hindukush and Himalayan ranges have created an impenetrable wall on the nothern side of the ________ subcontinent.
(a) Indian
(b) Foreign
(c) Asian
Answer:
Indian

Question 11.
There is a land route through the Khyber and Bolan passes in the ______ mountains.
(a) Himalayan
(b) Satpuda
(c) Hindukush
Answer:
Hindukush

Question 12.
The _____ desert spreads across Rajasthan, Haryana and some parts of Gujarat.
(a) Bhor
(b) Thar
(c) Arabian
Answer:
Thar

Question 13.
The _______ river that originates in Himachal Pradesh reaches the Thar desert.
(a) Ganga
(b) Sindhu
(c) Ghaggar
Answer:
Ghaggar

Question 14.
A region that is bound by sea on three sides is called a ______.
(a) peninsula
(b) plateau
(c) island
Answer:
peninsula

Question 15.
A major part of the Indian peninsula is occupied by the_______ plateau.
(a) Maharashtra
(b) Bengal
(c) Deccan
Answer:
Deccan

Question 16.
The mountain ranges of the Vindhya and Satpuda are located to the of the ________ Deccan Plateau.
(a) east
(b) north
(c) west
Answer:
north

Question 17.
Deccan plateau was a part of the ______ empire, the largest in ancient India.
(a) Maurya
(b) Gupta
(c) Chola
Answer:
Maurya

Question 18.
Lakshadweep is a group of Indian islands in the _____ Sea.
(a) Red
(b) Dead
(c) Arabian
Answer:
Arabian

Question 19.
The Harappan civilization had spread mainly in the ________ part of the Indian subcontinent.
(a) southeastern
(b) northwestern
(c) southwestern
Answer:
north western

Match the following:

Question 1.

Column (A)	Column (B)
(1) Himalayas	(a) South
(2) Indian Ocean	(b) East
(3) Arabian Sea	(c) North
(4) Bay of Bengal	(d) West

Answer:
1 – c
2 – a
3 – d
4 – b

Question 2.

Column (A)	Column (B)
(1) China	(a) Deccan plateau
(2) Vindhya range	(b) Not a part of Indian subcontinent
(3) Bangladesh	(c) In Bay of Bengal
(4) Andaman and Nicobar islands	(d) In the Hindukush mountains
(5) Khyber and Bolan passes	(e) Part of Indian subcontinent

Answer:
1 – b
2 – a
3 – e
4 – c
5 – d

Answer the following in one sentence:

Question 1.
Give the four major pillars without which history could not have been written.
Answer:
Time, place, society and individuals are the four major pillars of history, without which history could not have been written.

Question 2.
What has created an impenetrable wall on j the northern side of the Indian subcontinent? j
Answer:
Two mountain ranges, the Hindukush and Himalayan ranges have created an impenetrable wall on the northern side of the Indian subcontinent.

Question 3.
Which passes form a route in the Hindukush mountains?
Answer:
The Khyber and the Bolan passes form a land route in the Hindukush mountains.

Question 4.
What is known as ‘Hakra’ in Pakistan?
Answer:
The Ghaggar river that originates in Himachal Pradesh reaches the Thar desert. It is known as ‘Hakra’ in Pakistan.

Question 5.
Which plateau occupies a major part of the Indian peninsula?
Answer:
The Deccan plateau occupies a major part of the Indian peninsula.

Question 6.
Which mountain range is to the north of the Deccan plateau?
Answer:
The Vindhya and Satpuda mountain ranges are located to the north of the Deccan plateau.

Question 7.
Name the Indian islands in the Bay of Bengal.
Answer:
Andaman and Nicobar are the Indian islands in the Bay of Bengal.

Question 8.
Which manuscript mentions the Indian islands?
Answer:
The manuscript ‘Periplus of the Erythrean Sea’ or ‘Handbook of the Red Sea’ by an unknown Greek sailor, makes a mention of Indian islands.

Question 9.
Which two ancient cities are in today’s Pakistan?
Answer:
The cities of Harappa and Mohenjo-daro are in today’s Pakistan.

Answer the following questions in short:

Question 1.
State the extent of our country, India.
Answer:
Our country India, extends far and wide:

• To its north lies the Himalayas.
• To the east, the Bay of Bengal.
• To the west, the Arabian Sea.
• And to the south, the Indian ocean.
• Except for the islands of Andaman, Nicobar and Lakshadweep, the rest of the country is contiguous.

Question 2.
Describe the trade route from China to Arabia.
Answer:

• There is a land route through the Khyber and Bolan passes in the Hindukush mountains.
• This land route was connected to an ancient trade route.
• The trade route from China in the east passed through central Asia and reached Arabia in the west.

Give reasons:

Question 1.
The trade route from west to east was also called the silk route.
Answer:

• Silk was the main commodity exported to the western countries using this trade route.
• Therefore this trade route from west to east was called the ‘silk route’ or ‘silk road’.

Balbharti Maharashtra State Board Class 6 Geography Solutions Chapter 6 Importance of Oceans Notes, Textbook Exercise Important Questions and Answers.

Maharashtra Board Class 6 Geography Solutions Chapter 6 Importance of Oceans

Class 6 Geography Chapter 6 Importance of Oceans Textbook Questions and Answers

A. Find the odd man out:

Question 1.
Shell, fish, crab, ship
Answer:
ship

Question 2.
Arabian Sea, Mediterranean Sea, Dead Sea, Caspian Sea
Answer:
Dead Sea

Question 3.
Sri Lanka, India, Norway, Peru
Answer:
Sri Lanka

Question 4.
Southern Ocean, Indian Ocean, Pacific Ocean, Bay of Bengal
Answer:
Bay of Bengal

Question 5.
Natural gas, salt, gold, manganese
Answer:
Natural gas

B. Write the answers:

Question 1.
Which items does man get from the oceans?
Answer:
Salt, fish, shells and other products, minerals like iron, lead, cobalt, sodium, manganese, chromium, zinc, mineral oil and natural gas are the items man gets from oceans.

Question 2.
Why It is economic to carry out transport by water ways.
Answer:

• Waterways is a cost-effective, fuel efficient and relatively more environment friendly means of transportation.
• Large scale transport of goods can be carried out with the help of ships, trawlers, boats, etc. at a low cost.
• So it is economic to carry out transport by waterway.

Question 3.
Why There is a difference in the climate of regions close to the oceans and regions far away from the oceans.
Answer:
(i) The oceans influence the climatic condition of a place. Coastal areas are cooler and wetter than regions away from the ocean.

(ii) There is a difference in the maximum and minimum temperature with the difference being less in coastal region (nearness to the sea) while it is more in the region far away from the sea (continentality).

(iii) The temperature in coastal areas remains equable due to the mixing of vapour released through evaporation of water from these water bodies into air. This vapour absorbs and stores the heat released from the land.

Question 4.
Which continents are located along the coast of the Pacific Ocean?
Answer:
Asia, Australia, North America and South America are the continents located along the coast of the Pacific Ocean.

Activity:

Colour the different oceans on an outline map of the world and prepare an index for the map. (See inside front cover, figure B.)

Project:

Group work: Make five groups. Each group should collect some information and pictures of one ocean. With the help of the information collected, each group should make a poster and make presentation.

Class 6 Geography Chapter 6 Importance of Oceans InText Questions and Answers

Think a little!

Question 1.
Where does the water flowing through the rivers go in the end?
Answer:
The water flowing through the rivers goes into the oceans in the end.

Question 2.
Are there volcanic eruptions in the seas?
Answer:
Yes, volcanic eruptions take place in the seas.

Question 3.
What would have happened if man had not discovered sea routes?
Answer:

• If there were no sea routes, we would lose out on the most economic option of transportation.
• Large scale transport of goods would become inconvenient.
• International trade too would suffer.

Use your brain power!

Question 1.
Where did all this water on the earth come from?
Answer:
While some scientists believe that water was created due to the impact of comets there are others who believe that Earth’s waters have existed since the birth of planet earth.

Find out:

Question 1.
Collect information about how a natural pearl is formed.
Answer:

• Natural pearls form when an irritant- usually a parasite and not the proverbial grain of sand – works its way into an oyster, mussel, or clam.
• As a defense mechanism, a fluid is used to coat the irritant.
• Layer upon layer of this coating called ‘nacre’ is deposited until a pearl is formed.

Question 2.
Which oceanic organism develops in it?
Answer:
The oceanic organism oyster develops in it.

Question 3.
In which sea is it found in India?
Answer:
The Arabian Sea.

What will you do?

Question 1.
Different marine animals like the blue whale, turtle, starfish, etc. appear before you in your dream and complain to you. They say, “You humans are not allowing us to live properly. You throw the waste and chemicals that you do not want into our house. The youngsters in our house are falling ill due to this. Some are getting killed. You must think about this situation and remove the pollution from the seas.” Now tell what you will do.
Answer:
“Environmental problems begin with people as the cause and end with people as the victims.” Different ways to remove pollution from sea are:

• Creating awareness amongst people.
• Organising a clean-up operation.
• Insisting that government take steps to prevent marine pollution caused due to waste disposal.
• Following the principle of recycling waste and proper treatment of sewage before its disposal into water bodies.
• Generating a sense of responsibility amongst the citizens.

Can you do it?

Question 1.
Sameer and Sania are playing a game of showing the waterways on a map of the world. Their routes are going in opposite directions. One of the following the eastern route while the other is making a route that takes to the west.

From Mumbai port some goods are to be taken to London in UK. On a map of the world, show at least two such routes with a pencil.
Write down the names of the ports of different nations that fall on the route followed by each.

Ports on the route followed by Sameer:

Answer:

• JNPT – India
• Nish tun – Yemen
• Salal – Oman
• Port of Berbera – Somalia
• Port of A1 Qusayr – Egypt
• Port of Said – Egypt Suez
• port – Egypt
• Port of Tenes – Algeria
• Port of Tunis – Tunisia
• Port of Bone facia – France
• Port of Aguilas – Spain
• Port of Adra – Spain
• Port of Gibraltar – Gibraltar
• Port of Sines – Portugal
• Swange Pier – UK
• Whitstable harbour – UK
• Purfleet Thames Terminal – UK
• Port of London – UK

Ports on the route followed by Sania:

• Port of Mergui – Myanmar
• Port of Ramong – Thailand
• Port of Krueng Raya – Indonesia, etc.

Question 2.
Which of the routes you feel is shorter? That of Sameer’s or Sania’s?
Answer:
Sameer’s route is shorter.

Question 3.
Which oceans does one have to pass through if one follows Sameer’s route or Sania’s route?
Answer:
If one follows Sameer’s route one has to pass through the Indian Ocean and North Atlantic Ocean. If Sania’s route is taken she has to pass through the Pacific and North Atlantic Ocean.

Question 4.
What are Panama and Suez? For what purpose were they constructed?
Answer:

• Panama and Suez are the canals in the sea built for commercial purpose.
• It helped in saving time, money and energy and gave a fillip to international trade due to the shorter distance and easy accessibility.

Question 5.
Have they been used in Sameer’s and Sania’s routes?
Answer:
Yes, Suez Canal is used in Sameer’s route while Panama Canal is used in Sania’s route.

Class 6 Geography Chapter 6 Importance of Oceans Additional Important Questions and Answers

Fill the blanks choosing the correct alternatives from the brackets:

Question 1.
The ______ includes all the water bodies like oceans, seas, rivers and their tributaries, lakes, reservoirs and also ground water that exist on the earth.
(lithosphere, atmosphere, hydrosphere)
Answer:
hydrosphere

Question 2.
Total global water 97.7% is contained in ______ (lakes, oceans, seas)
Answer:
oceans

Question 3.
The ocean with an area 166,240,977 sq. km is the _______ ocean. (Indian, Atlantic, Pacific)
Answer:
Pacific

Question 4.
All rivers flowing from mountains or hilly areas finally meet in the ________.(lakes, seas, oceans)
Answer:
oceans

Question 5.
Salinity is expressed in terms of ______.(mils, ml, gms)
Answer:
mils

Question 6.
The average salinity of oceanic water is _______.(80%, 332%, 35%)
Answer:
35%

Question 7.
The salinity of the Dead Sea is _____.(332 %, 35%, 60%)
Answer:
332 %

Question 8.
About ________ of the surface of the earth is occupied by water. (90%, 95%, 70.8%)
Answer:
70.8%

Question 9.
Salt as a substance is obtained by constructing ______. (sea bed, salt pan, river bunds)
Answer:
salt pan

Question 10.
________ is conducted on a much higher scale as compared to the other modes of transport. (Water transport, Air transport, Road transport)
Answer:
Water transport

Question 11.
Pollution of _________ water is caused due to oil spills. (river, lake, oceanic)
Answer:
oceanic

Question 12.
Winds blowing due to pressure difference in the belts is called ______. (planetary winds, oceanic winds, minerals)
Answer:
planetary winds

Match the pairs correctly:

Question 1.

Oceans	The area in sq. km
(1) Pacific	(a) 20,327,000
(2) Atlantic	(b) 73,426,163
(3) Indian	(c) 166,240,977
(4) Southern	(d) 13,224,479
(5) the Arctic	(e) 86,557,402

Answer:
1 – c
2 – e
3 – b
4 – a
5 – d

Find the odd man out:

Question 1.
Pearls, corals, diamonds, medicinal plants
Answer:
diamonds

Question 2.
Spain, Norway, Japan, India
Answer:
India

Question 3.
Blue whale, sea turtles, seerfish, dolphins
Answer:
seerfish

Name the following:

Question 1.
Water bodies which are a part of the . hydrosphere.
Answer:
Oceans, seas, rivers and their tributaries, lakes, reservoirs, ground water.
Question 2.
Percentage of global waters contained in oceans.
Answer:
97.7%

Question 3.
Two aquatic animals found in the ocean.
Answer:

• Microscopic planktons
• Huge whales

Question 5.
Places where volcanic eruptions occur.
Answer:

• Land
• Ocean

Question 6.
Two minerals obtained from the sea.
Answer:

• Phosphates
• Sulphates

Question 7.
Two uses of marine animals.
Answer:

• Production of fertilisers
• Production of pharmaceuticals

Question 8.
Two countries with coastline which largely depends on the sea for their livelihood.
Answer:

• Seychelles
• Mauritius

Question 9.
The controller of global temperature and source of rains.
Answer:
Oceans.

Question 10.
The beginning and end of the water cycle takes place here.
Answer:
Oceans.

Question 11.
Two minerals obtained from the ocean floor.
Answer:

• Cobalt
• Sodium

Question 12.
Precious items obtained from the seas.
Answer:

• Pearls
• Corals

Question 13.
Mode of transport used for large scale transportation of goods.
Answer:

• Ships
• Trawlers

Question 14.
Two actions by man which has lead to large scale pollution in oceanic waters.
Answer:

• Oil spills
• Exploitative fishing

Answer the following in one sentence each:

Question 1.
What happens when aquatic animals die?
Answer:
When aquatic animals die, their remains accumulate in the oceans.

Question 2.
What enters the ocean with the rain water?
Answer:
Sediments from eroded lands, trees and bushes flowing with water, dead remains, etc. enter the ocean with the river water.

Question 3.
What happens when the dead remains in the ocean decompose?
Answer:
When the dead remains in the oceans decompose it releases various minerals and salts in the ocean water.

Question 4.
Where do we find maximum salinity?
Answer:
The Dead Sea is known to have the maximum salinity of 332%.

Question 5.
How is salt obtained?
Answer:
Salt as a substance is obtained by constructing salt pans in the coastal areas.

Question 6.
Which is one of the ancient occupations of human beings and what is the major purpose of his activity?
Answer:
Fishing is one of the ancient occupation and the major purpose of this activity is to obtain food.

Question 7.
How does the earth get rainfall?
Answer:
The oceans have a vast expanse, therefore huge amounts of vapour get created and this process goes on continuously and from this vapour the earth gets rainfall.

Question 8.
How is pollution caused in oceanic water?
Answer:
In order to fulfill his requirements, man undertakes many activities that lead to the production of huge amounts of different types of waste materials which cause pollution.

Question 9.
Write anyone cause of pollution of oceanic waters.
Answer:
Cutting of mangroves forests in coastal areas is one of the main cause of pollution in oceanic waters.

Question 10.
How does oceanic pollution affect the aquatic animals?
Answer:
Due to oceanic pollution many aquatic animals are under the threat of being extinct. For example, the blue whale, some types of sea turtles, dolphins, etc.

Question 11.
Which items does man get from the oceans?
Answer:
Salt, fish, shells and other products, minerals like iron, lead, cobalt, sodium, manganese, chromium, zinc, mineral oil and natural gas are the items man gets from oceans.

Question 12.
Which continents are located along the coast of the Pacific Ocean?
Answer:
Asia, Australia, North America and South America are the continents located along the coast of the Pacific Ocean.

Give geographical reasons for the following statements:

Question 1.
The ocean water is saltier than drinking water.
Answer:

(i) In drinking water, the proportion of salts is quite low. Water from oceans and seas has a greater amount of salt. Hence it tastes salty.

(ii) Volcanic eruptions leads to increase in the level of salts and minerals in ocean water.

(iii) Volcanic eruptions takes place in the oceans. During volcanic eruptions different minerals, ashes, salts and gases are added to the water. This increases the level of salts and minerals in ocean water.

(iv) Due to continuous evaporation of oceanic water, the proportion of salt increase.

Question 2.
The temperature in coastal areas remains equable.
Answer:

(i) In regions close to the oceans, seas or large reservoirs, there is not much of a difference in the temperature throughout the day.

(ii) The main reason for this is the mixing of vapour released through evaporation of water from these water bodies into air.

(iii) This vapour in the air absorbs and stores the heat released from the land.

(iv) Hence, the temperature in coastal regions remain equable.

Question 3.
It is economic to carry out transport by water ways.
Answer:

• Waterways is a cost-effective, fuel efficient and relatively more environment friendly means of transportation.
• Large scale transport of goods can be carried out with the help of ships, trawlers, boats, etc. at a low cost.
• So it is economic to carry out transport by waterway.

Question 4.
There is a difference in the climate of regions close to the oceans and regions far away from the oceans.
Answer:
(i) The oceans influence the climatic condition of a place. Coastal areas are cooler and wetter than regions away from the ocean.

(ii) There is a difference in the maximum and minimum temperature with the difference being less in coastal region (nearness to the sea) while it is more in the region far away from the sea (continentality).

(iii) The temperature in coastal areas remains equable due to the mixing of vapour released through evaporation of water from these water bodies into air. This vapour absorbs and stores the heat released from the land.

Question 5.
Oceans act as the controller of global temperature.
Answer:

(i) Winds move the oceanic water in the form of currents.

(ii) Ocean currents move from the equatorial region to polar regions and from polar regions to the equatorial region.

(iii) This leads to the redistribution of heat on the earth.

(iv) The cold currents moving towards the equatorial region making the temperature of coastal areas in that zone milder whereas the warm currents coming in the colder region cause the temperature in coastal areas to rise. Hence, the oceans act as the controller of global temperature.

Answer the following questions in brief:

Question 1.
What are planetary winds?
Answer:

• Equatorial regions receives perpendicular sunrays.
• As a result these areas get more heat whereas the polar regions receive highly slant rays.
• This differential heating creates imbalance in the temperature of air in different parts leading to formation of belts of high and low pressure on earth.
• Winds blow1 due to the pressure differences in these belts. These winds are called Planetary Winds.

Question 2.
Write in brief about oceanic transport.
Answer:

• Oceans have provided us the most economic option of transportation.
• Large scale transportation of goods is carried out with the help of ships, trawlers, boats, etc.
• International trade is carried out on a large scale using waterways.
• Countries like Spain, Norway, Japan have a good coastline due to which goods are transported by ocean routes, making these countries important.

Question 3.
How do ocean currents aid water transport?
Answer:

• Ocean currents are quite important in water transport.
• As far as possible water transport is carried out along ocean currents.
• They accelerate the speed of the ships and also save fuel to a considerable extent.

Question 4.
List the causes that lead to large scale pollution of oceanic water.
Answer:
The causes that lead to large scale pollution of oceanic water are:

• Oil spills.
• Releasing the waste produced in the coastal cities into the seas.
• Materials thrown out from ships.
• Exploitative fishing.
• Cutting of mangrove forests in coastal areas.
• Disasters caused by the water mines.
• Sewage released by industries and cities.
• Excavation carried out in the seas.

Do it yourself!

Question 1.
Calculate the difference between the mean maximum and minimum temperature and write in the last column

Place	Country	Mean Max. Temp. °C	Mean Min. Temp. °C	Range of Temperature
Beijing	China	18.4	08.4	10
Istanbul	Turkey	18.0	10.0	08		_______
Madrid	Spain	19.0	09.0	10
New York66	United States	16.3	08.3	08		________
Denver	United States	16.2	02.2	14
Kabul	Afghanistan	14.7	05.2	09.5		________
Baghdad	Iraq	30.4	14.7	15.7

Question 2.
Highlight the rows for the places having a range of temperatures over 10°C with red colour, other rows in blue colour (Refer the above table)
Question 3.
Find the locations of these places from an atlas. (Students activity)
Question 4.
Which places are closer to the oceans? Tell whether the range of temperature at these
places is l ess or more?
Answer:
Istanbul and New York are closer to the oceans. These places which are closer to the oceans have lesser range of temperature.

Question 5.
What might be the main reason leading to differences in the temperature range in different places?
Answer:
The main reason leading to differences in temperature range in different places is because of the location of the place on the planet earth. Other factors like latitude, altitude, atmosphere, ocean currents, planetary winds etc. too have their impact.

Question 6.
In which thermal zone are all these places located?
Answer:
All these places are located in the temperate thermal zone.

Question 7.
Which places are fai away from the oceans?
Do these places have a greater or smaller temperature range?
Answer:
Istanbul, Denver, Kabul and Baghdad are far away from the ocean as these places have a greater temperature range.

Question 8.
Mention the places having the smallest and greatest temperature ranges.
Answer:
Istanbul and New York have the smallest temperature range while Baghdad has the greatest temperature range.

Question 9.
Draw a graph for the above data. Use a proper colour scheme.
Answer:

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 10 Cell and Cell Organelles Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 8 Science Solutions Chapter 10 Cell and Cell Organelles

Class 8 Science Chapter 10 Cell and Cell Organelles Textbook Questions and Answers

1. Who am I?

Question a.
I am ATP producing factory.
Answer:
Mitochondria

Question b.
I am single-layered but maintain cellular osmotic pressure.
Answer:
Vacuole

Question c.
I support the cell, but I am not cell wall. I have a body resembling net.
Answer:
Endoplasmic reticulum

Question d.
I am chemical factory of the cell.
Answer:
Chloroplasts in case of plant cells can be called chemical factory as they synthesise carbohydrates. Ribosomes also synthesise proteins, so those can also be called chemical factory. Golgi complex is secretory in function, hence it can be also called factory. Mitochondria though mainly referred to as powerhouse of the cell, it is also mentioned as chemical factory by some authors.

Question e.
Leaves are green because of me.
Answer:
Chloroplast.

2. What would have happened? If……….

Question a.
RBCs had mitochondria.
Answer:
Mitochondria continuously carry out oxidation and form energy inside the cell. They produce energy-rich compound, ATP. In this process, they utilize carbohydrates, fats and proteins present in the cell. If RBCs has mitochondria, they would have used oxygen for this purpose than carrying it to all the cells of the body. The cells would not have obtained oxygen.

Question b.
There had been no difference between mitochondria and plastids.
Answer:
Mitochondria carry out oxidation of carbohydrates, fats, etc. with the help of enzymes. Plastids are synthesising carbohydrates with the help of solar energy and chlorophyll. Both the cell organelles have their own sets of different enzymes as per their role. If there would have been no difference between mitochondria and plastids, the specific functions would not have been taken place.

Question c.
Genes had been absent on the chromosomes.
Answer:
Genes are functional segments on the chromosomes which are responsible for transmitting the hereditary information.

Question d.
Plasma membrane had not been selectively permeable.
Answer:
Selectively permeable membrane allows some substances to enter the cell, while prevents other unwanted or harmful substances. If plasma membrane would not have been selectively permeable, there would be no control over entry and exit of any substances. The process of osmosis would also be erroneous in such case.

Question e.
Plants lacked anthocyanin.
Answer:
If plants lacked anthocyanin, no part of the plant would display purple or blue colour. Anthocyanin attracts the insects for pollination and seed dispersal. These processes will be affected due to lack of anthocyanin. These pigments are also said to be protective in nature for the plant. This protection will not be given to the plant in absence of anthocyanin.

3. Who is odd man among us? Give reason.

Question a.
Nucleolus, mitochondria, plastids, endoplasmic reticulum
Answer:
Nucleolus. (All the others are cell organelles but nucleolus is not a cell organelle present in cytoplasm.)

Question b.
DNA, Ribosomes, Chlorophyll
Answer:
Chlorophyll. (DNA and Ribosomes are present in plant as well as in animal cells. Chlorophyll is present only in plant cells.)

4. Give functions.

Question a.
Plasma membrane.

Answer:

1. Plasma membrane acts as a selectively permeable membrane. It allows entry of those useful substances which are needed for the cell. It does not allow entry of the harmful and unwanted substances.
2. Plasma membrane keeps the homeostasis in the cell. The cell is kept in steady state even if the external environment changes.
3. Plasma membrane is responsible for processes of endocytosis and exocytosis.
4. The processes of diffusion and osmosis are possible only due to plasma membrane.
5. In animal cells, plasma membrane is the outermost protective covering of the cell.

Question b.
Cytoplasm.
Answer:

1. All the cell organelles are spread in the cytoplasm of a cell.
2. The cytoplasm is the medium for many cellular chemical reactions.
3. The cytosol which is the part of cytoplasm other than cell organelles stores many vital substances like amino acids, glucose, vitamins, etc.
4. Cytosol also helps in the cellular movements.

Question c.
Lysosome.

Answer:

1. Lysosome helps in the destruction of attacking viruses and bacteria and thereby help in the immune response.
2. Lysosomes act as demolition squads. They destroy worn-out cellular organelles and organic debris. This process is called autolysis which All Pagesmeans self-destruction.
3. They are also called suicide bags as in a worn out, damaged or old cell, lysosomes automatically burst. The lytic enzymes present in the lysosome digest their own cells.
4. Lysosomes can digest stored proteins, fats during starvation.

Question d.
Vacuole.

Answer:

1. Vacuoles maintain the osmotic pressure of the cell.
2. Various metabolic byproducts and end products such as glycogen, proteins, water, etc. are stored in the lysosome.
3. In food vacuole of amoeba, the food is temporarily stored till digestion. In other animal cells, vacuoles can store waste products and food.
4. Vacuoles of plant cells can provide turgidity and rigidity as it contains good amount of cell sap.

Question e.
Nucleus.

Answer:

1. Nucleus is the controlling centre for the entire cell.
2. It controls all metabolic activities of the cell.
3. The cell division is possible due to the nucleus.
4. The chromosomes present in the nucleus carry the genes. These genes are responsible for the transmission of hereditary characters from parental generation to the next generations.

5. Who gives me the colour? (Select the correct option).

Question a.

Column ‘A’	Column ‘B’
1. Red tomato	a. Chlorophyll
2. Green leaf	b. Carotene
3. Carrot	c. Anthocyanin
4. Violet	d. Lycopene

Answer:

Column ‘A’	Column ‘B’
1. Red tomato	d. Lycopene
2. Green leaf	a. Chlorophyll
3. Carrot	b. Carotene
4. Violet	c. Anthocyanin

Project:

Question 1.
Prepare model of a cell using different ecofriendly materials.

Question 2.
Study osmosis using parchment paper or a similar membrane.

Question 3.
Form a friends’ group in your class. Give each one role of a cell organelle. Present a skit accordingly.

Class 8 Science Chapter 10 Cell and Cell Organelles Important Questions and Answers

Rewrite the sentences after filling the blanks:

Question 1.
Cell wall is mainly composed of carbohydrates like ……….. and …………. .
Answer:
Cell wall is mainly composed of carbohydrates like cellulose and pectin.

Question 2.
Plasma membrane is said to be a ……………. …………….. membrane as it allows some substances to enter the cell, while prevents other substances.
Answer:
Plasma membrane is said to be a selectively permeable membrane as it allows some substances to enter the cell, while prevents other substances.

Question 3.
Homeostasis is maintained in the cell by ………….. .
Answer:
Homeostasis is maintained in the cell by plasma membrane.

Question 4.
An …………… is a specialized subunit having specific function within the cell.
Answer:
An organelle is a specialized subunit having specific function within the cell.

Question 5.
……………. has ribosome granules on its outer surface.
Answer:
Rough ER has ribosome granules on its outer surface.

Question 6.
During starvation, ………………… digest stored proteins, fats.
Answer:
During starvation, lysosomes digest stored proteins, fats.

Question 7.
……………….. is the secretory organ of the cell.
Answer:
Golgi complex is the secretory organ of the cell.

Question 8.
……………. compound ATP is produced in the mitochondria.
Answer:
Energy-rich compound ATP is produced in the mitochondria.

Given below are incorrect statements. Rewrite them after correcting them:

Question 1.
In mitochondria, the inner membrane is porous and the outer membrane is deeply folded.
Answer:
In mitochondria, the outer membrane is porous and the inner membrane is deeply folded.

Question 2.
Vacuole is bound by double membrane.
Answer:
Vacuole is bound by single membrane.

Question 3.
If fruit pieces are kept in thick saturated sugar solution, the water from fruit pieces enter the sugar solution resulting into their swelling.
Answer:
If fruit pieces are kept in a thick saturated sugar solution, the water from fruit pieces enter the sugar solution resulting into their shrinking.

Question 4.
Raisins kept in water shrink after an hour.
Answer:
Raisins kept in water swell after an hour.

Question 5.
Lysosome produces vacuoles and secretory vesicles.
Answer:
Golgi complex produces vacuoles and secretory vesicles.

Who gives me the colour? (Select the correct option)

Question 1.

Column ‘A’	Column ‘B’
1. Nucleus	a. Pipelines of the cell
2. Endoplasmic reticulum	b. Powerhouse of the cell
3. Golgi complex	c. Suicidal bags
4. Mitochondria	d. Packing department
5. Lysosomes	e. Controlling centre

Answer:

Column ‘A’	Column ‘B’
1. Nucleus	e. Controlling centre
2. Endoplasmic reticulum	a. Pipelines of the cell
3. Golgi complex	d. Packing department
4. Mitochondria	b. Powerhouse of the cell
5. Lysosomes	c. Suicidal bags

Find the odd one out by giving suitable reasons:

Question 1.
Demolition squads, Suicide Bags, Immune system, Powerhouse of the cell.
Answer:
A powerhouse of the cell. (All the others are descriptions of the lysosomes.)

Question 2.
Lignin, Suberin, Cutin, Iodine
Answer:
Iodine. (All the others are polymers present in the cell wall.)

Question 3.
Nucleolus, Genes, Chromosomes, Ribosomes
Answer:
Ribosomes. (All the others are inclusions in the nucleus.)

Write definitions/Give meanings:

1. Homeostasis: The tendency of the cell to keep the cellular environment constant in spite of changes in the outer: environment is called homeostasis.

2. Endocytosis: To take in the food or any other substance from outer environment into the cell is called endocytosis.

3. Exocytosis: To give out the unwanted substances from the cell to the outer « environment is called exocytosis.

4. Diffusion: The movement of the molecules from region of higher concentration to the region of lower concentration is called diffusion.

5. Osmosis: The movement of solute from low concentration to high concentration and the movement of solvent from high concentration to the region of low concentration across semipermeable membrane is called osmosis.

6. Plasmolysis: When the cell is kept ?! in hypertonic medium, the water exits through the process of exosmosis causing shrinkage of the cytoplasm, this is known as plasmolysis.

7. Isotonic solution: When the concentration of the cell and that of the medium in which the cell is kept is same, then such solution is called isotonic solution.

8. Hypotonic solution: When the concentration of the water in the cell is less than that of the concentration of the water in the surrounding medium in which the cell is kept, then such solution is called hypotonic solution.

9. Hypertonic solution: When the concentration of the water in the cell is more than that of the concentration of water in the surrounding medium then such solution is called hypertonic solution.

Distinguish between the following:

Question 1.
Prokaryotic and eukaryotic cell:
Answer:

Prokaryotic cell	Eukaryotic cell
1. Nucleoid is present instead of a well-formed nucleus.	1. Nucleus is well-formed with nuclear membrane, chromatin network and nucleolus.
2. Chromosome number is always one.	2. Chromosome number is more than one and is specific for every species.
3. Membrane-bound cell organelles are absent.	3. There are membrane-bound cell organelles.
4. The size of the cell is 1 to 10 micrometre. Example: Bacteria	4. The size of the cell is 5 to 100 micrometre. Example: All highly evolved unicellular and multicellular plants and animals.

Question 2.
Plant cell and animal cell
Answer:

Plant cell	Animal cell
1. The cell wall is the outermost covering on the cell. The plant cells have both cell wall and the cell membrane	1. The cell membrane or plasma membrane is the outermost covering of the cell. The animal cells do not have cell wall
2. The vacuoles are large and centrally placed.	2. The vacuoles are small and uniformly distributed in the cytoplasm.
3. There are plastids in the plant cells. The chloroplasts have chlorophyll.	3. The plastids are absent in the animal cells.
4. The lysosomes are absent in the plant cells.	4. Lysosomes are present in the animal cells. They contain digestive enzymes.
5. The cytoplasm is thin and pushed to the periphery due to central vacuole.	5. The cytoplasm is dense and granular. It is uniformly spread throughout the cell.

Answer the following questions in one sentence:

Question 1.
What are the components of plasma membrane?
Answer:
In plasma membrane, protein molecules are embedded in two layers of phospholipids.

Question 2.
Which part of the cell maintains the homeostasis?
Answer:
Plasma membrane of the cell maintains the homeostasis.

Question 3.
What are genes?
Answer:
Genes are the functional segments on the chromosomes that carry hereditary i information from the parental generation to the offspring.

Question 4.
What is meant by rough ER?
Answer:
The endoplasmic reticulum that has ribosomes on its outer membrane is called rough ER.

Question 5.
Write the examples of plant pigments.
Answer:
Chlorophyll, Carotene, Xanthophyll, Anthocyanin, Betalains and Lycopene are some of the plant pigments.

Question 6.
What are the inclusions in the stroma of chloroplasts?
Answer:
Enzymes, DNA, ribosomes and carbohydrates that are necessary for photosynthesis are present in the stroma of the chloroplasts.

Question 7.
Which staining technique was developed by Camilio Golgi? Where was this technique used?
Answer:
Camilio Golgi developed the staining technique called ‘Black reaction’ which was used in the study of nervous system.

Question 8.
What type of work is done by National Centre for Cell Science?
Answer:
National Centre for Cell Science – NCCS is involved in research in cytology and research about cancer treatment and it also provides services for National Animal cell repository.

Question 9.
Ripe tomatoes appear red.
Answer:
When green tomatoes become ripe they lose chlorophyll and develop red pigment in them called lycopene. Therefore, ripe tomatoes appear red.

Give scientific reasons:

Question 1.
Raisins swell after keeping in plain water.
Answer:
When raisins are placed in plain water, there is action of endosmosis. The outer skin of raisins acts like selectively permeable membrane. Since the concentration of water inside the raisin is lesser than the concentration of water in the outer medium, water enters in the raisin. This causes raisins to swell after keeping them in plain water.

Question 2.
The fruit pieces kept in sugar syrup show shrinking.
Answer:
There is more concentration of water in the fruit pieces as compared to the concentration of water in the sugar syrup. Therefore, water is lost out by exosmosis. The membranes of the fruit pieces act as selectively permeable membranes. Thus the process of plasmolysis occurs resulting into shrinking of the fruit pieces.

Question 3.
The nucleus of the sieve tubes of the plant phloem is lost.
Answer:
The sieve tubes of the plant phloem conduct the food in plants. To make this transport easier, the nucleus of the sieve tubes of the plant phloem is lost,

Question 4.
Plant cells have less mitochondria than those of animal cells.
Answer:
Mitochondria are the cell organelles which are called powerhouse of the cell. They produce energy in the form of ATP. Animals are motile and need more energy for walking, running and moving. Plants are stationary. They do not need energy to greater extent. Therefore, they have lesser number of mitochondria.

Question 5.
Vacuoles do not have any typical size or shape.
Answer:
Vacuoles change their shape and size as per the need of the cell. Thus they do not have any fixed shape or size.

Question 6.
Ripe tomatoes appear red.
Answer:
When green tomatoes become ripe they lose chlorophyll and develop red pigment in them called lycopene. Therefore, ripe tomatoes appear red.

Give functions:

Question 1.
Endoplasmic reticulum.

Answer:

1. Endoplasmic reticulum or ER is the supporting framework of the cell.
2. The ribosomes attached to the membrane of the ER synthesize proteins. These proteins are conducted by ER.
3. The detoxification process is done by ER. The toxins that enter the cell through food, air and water are removed out by making them water soluble.

Question 2.
Golgi complex.

Answer:

1. Different secretions are prepared in the Golgi complex. Hence it is called the secretory organ of the cell.
2. The secretions are modified and sorted out as per their functions. They are further packed.
3. The enzymes, mucus, proteins, pigments, etc. are sorted and then dispatched to various target regions like plasma membrane, lysosome, etc.
4. Golgi complex also produces vacuoles and secretory vesicles.
5. Formation of cell wall, plasma membrane and lysosomes is aided by Golgi complex.

Question 3.
Plastids.
Answer:

1. Chloroplasts contain chlorophyll. They carry out the process of photosynthesis. They convert solar energy to chemical energy in the form of food.
2. Chromoplasts with different pigments can impart different colours to flowers and fruits.
3. Leucoplasts are responsible for the synthesis and storage of food like starch, oils and proteins.

Answer the following questions:

Question 1.
How does endosmosis and exosmosis occur in the cell?
Answer:

1. When the water concentration inside the cell is less as compared to the medium in which it is present, then the endosmosis takes place. This makes the water to enter inside the cell.
2. When water concentration inside the cell is more than the water concentration in the medium in which it is present, then the water comes out of the cell. This is called exosmosis.
3. Since the cell membrane acts as a semipermeable membrane, the processes of endosmosis and exosmosis takes place in the cell.

Question 2.
What is cytoplasm? What are the constituents of cytoplasm?
Answer:

1. The jelly like material present between the cell membrane and nucleus is called cytoplasm.
2. Cytoplasm without cell organelles is called cytosol.
3. All the cell organelles are spread in the cytoplasm.
4. Cytosol stores many vital constituents such as amino acids, glucose, vitamins, etc.
5. The cytoplasm of animal cells is dense and granular while that of plant cells is thin and peripheral. It is pushed to sides due to large central vacuole.

Question 3.
Describe the structure of the nucleus in the cell.

Answer:

1. Nucleus is the most important part of the eukaryotic cell.
2. Inside the nucleus there is round darkly stained nucleolus.
3. The nucleus is covered over by double membrane which is porous.
4. The nuclear pores allow the transport of different substances in and out of the nucleus to cytoplasm.
5. Inside the nucleus is the chromatin network which contains chromosomes. Chromatin fibres are thin which condense to form chromosomes. The chromosomes become clear and distinct at the time of cell division.
6. In every cell there are specific number of chromosomes. Chromosomes contain genes which are bearers of hereditary characters.

Question 4.
Why is endoplasmic reticulum compared with the pipelines?
Answer:

1. The endoplasmic reticulum works as pipelines to carry different substances in the cell.
2. It is a net like structure consisting of interconnected small tubes and sheets filled with fluid.
3. On the inner side the E.R. is connected to nucleus while at the outer side it is in contact with plasma membrane. Therefore, it works like a pipeline.

Question 5.
Write an account of the different structures seen in Golgi complex.
Answer:

1. Golgi complex is made up of 5-8 hollow and flat sacs called cisternae.
2. These are placed parallel to each other and are filled with different enzymes.
3. Golgi complex has two faces called forming face and maturation face.
4. The proteins packed in vesicles and coming from ER reach Golgi complex through cytoplasm.
5. They fuse with the formation face of the Golgi membranes for emptying their contents in the cisternae.
6. When these contents pass through the cisternae, they are chemically modified with the help of enzymes and are again packed in the vesicles.
7. These vesicles come out of Golgi ‘ complex at the maturation face.

Question 6.
How is energy produced in the mitochondria? How the structures of mitochondria help in this process?
Answer:

1. Around every mitochondrion there is a double membrane.
2. The outer membrane of these is porous while the inner membrane is deeply folded.
3. These folds or ‘cristae’ enclose the matrix filled with proteinaceous gel containing ribosomes, phosphate granules and DNA. Protein synthesis takes place in this matrix.
4. Mitochondria carry out oxidation of carbohydrates and fats in the cell. This produces energy in the form of ATP, s i.e. Adenosine Tri Phosphate

Question 7.
What is the benefit of foldings of inner membrane in mitochondria?

Answer:
The structure of the inner mitochondrial membrane is extensively folded and compartmentalized. The numerous imaginations of the membrane are called cristae. This folded inner membrane increases the area which is about 5 times more than that the outer membrane due to cristae. Cristae membranes have small round protein complexes known as Fx particles. In these particles the process of energy production goes on.

Research:

Question 1.
Keep 4 – 5 raisins in water and observe after an hour. Afterward, keep the same raisins in sugar solution and observe after an hour. Note down the observations and discuss in the classroom.
Answer:
When raisins are kept in water its outer skin acts as a semi-permeable membrane. The water content inside the raisin is lesser as compared to the water content in the outside medium. Therefore the water enters in the raisins due to process of endosmosis. Thus if raisins kept in plain water are observed after one hour, they are seen to be swollen.

On the other hand, if raisins are kept in sugar solution, they show plasmolysis and they shrink. The sugar solution acts as hypertonic medium. Water content in the raisin is higher than that present in the sugary solution. Thus water exists from raisins and its content thus shrinks.

Question 2.
Wooden doors fit very tightly in rainy season. Why does it happen?
Answer:
During rainy season there is more humidity in air. The doors get soaked in rain water. Though wood is non-living, it has the ability to absorb water. As the moisture is more in the surrounding area, it enters the wood. This is a type of endosmosis. It causes the doors to swell. The swollen doors then fit very tightly.

Diagram based questions:

Question 1.
Structure of the cell:

Answer:

(iii) Complete the chart:

Answer:

Component	Animal cell	Plant cell
Cell membrane	Present	Present
Cell wall	Absent	Present
Lysosomes	Present	Absent
Plastids	Absent	Present
Endoplasmic reticulum	Present	Present
Vocuole	Present	Present
Golgi complex	Present	Present
Mitochondria	Present	Present

Question 2.
Sketch the diagrams to show how osmosis occurs in plant cell if kept separately in isotonic, hypotonic and hypertonic medium.
Answer:

Question 3.
Sketch the diagrams to show how osmosis occurs in animal cell if kept separately in isotonic, hypotonic and hypertonic medium
Answer:

Activity-based questions:

Question 1.
Experiment Activity – Take a drop of water on a clean glass slide. Using an ice-cream spoon, gently scrap the inner surface of your cheek. With a needle, transfer a little material from spoon to the water drop on the slide and spread it evenly. Put a drop of methylene blue stain on the smear. Put a cover slip and observe under microscope. Did you observe the cells with blue nucleus?
Answer:
Students should do this activity at school laboratory. There are squamous epithelial cells in the inner side of the cheek. When stained with methylene blue the nucleus takes up dark stain and can be seen clearly.

Question 2.
Experiment Activity – Take out a thin peel of Rheo or Croton leaf and observe the chromoplasts under the compound microscope.
Answer:
Students are expected to do the observations in the school laboratory.

Question 3.
Can you recall? Observe the cells of onion peel under the microscope. Have you seen the fully turgid, rectangular cells of onion peelings?

Answer:
Students are expected to do the observations in the school laboratory.

Balbharti Maharashtra State Board Class 6 Geography Solutions Chapter 5 Temperature Notes, Textbook Exercise Important Questions and Answers.

Maharashtra Board Class 6 Geography Solutions Chapter 5 Temperature

Class 6 Geography Chapter 5 Temperature Textbook Questions and Answers

A. Where am I?

Question 1.
The isotherm 0°C runs in my surroundings:
Answer:
Northern Asia/Northem Canada.

Question 2.
The mean annual temperature is 25°C around me:
Answer:
Central Africa.

Question 3.
The mean annual temperature around me is 10°C:
Answer:
Northern Europe/Central Asia/USA.

B. Who am I?

Question 1.
I connect places of equal temperature.
Answer:
Isotherm.

Question 2.
I am useful for measuring the correct temperature.
Answer:
Simple thermometer.

Question 3.
I get heated due to the land or water near me.
Answer:
Air.

Question 4.
Land and water gets heated due to me.
Answer:
Sunrays.

C. Answer the following:

Question 1.
Explain with a diagram, the effect of the spherical shape of the earth on the temperature at different latitudes.
Answer:

• Due to the spherical shape of the earth and the resultant curvature of the surface, sunrays occupy a larger or a lesser area.
• Equatorial regions which receive straight rays of the sun occupy less space and heat received is more.
• Polar regions receive slant rays of the sun occupy larger space but the heat received is less.

Question 2.
What is the relation between the latitudinal extent and temperature of a region?
Answer:

• 0° and 23° 30′ North and South perpendicular rays. Temperatures are higher throughout the year.
• 23° 30′ and 66° 30′ North and South receive extreme slant rays. Temperatures are moderate.
• 66° 30′ and 90° North and South receive extreme slant rays. Temperatures are very low.

Question 3.
What makes the isotherms run zigzag over continental areas?
Answer:
Isotherms run zigzag over continental areas because the temperature is influenced by its physical set up and height above the mean sea level on the continent.

Activity:

• Use the thermometer in your school and note the daily temperature on a display board.
• For two weeks, take down in your notebook, the information regarding weather given in the daily newspapers. Discuss your notes in the classroom.

Class 6 Geography Chapter 5 Temperature InText Questions and Answers

Can you tell?

Question 1.
Find the range of temperature at Mumbai, Nagpur and Srinagar. Draw bar graphs for the same.
Answer:
Annual Range of temperature in °C

Region	Min. temperature	Max. temperature
Mumbai	20.5	32
Nagpur	22	44
Srinagar	2.5	24

Answer the following questions with the help of figure:

Question 1.
What is the tube of the thermometer fixed on ?
Answer:
The tube of the thermometer is fixed on a mount.

Question 2.
What substance is used in the thermometer tube?
Answer:
Mercury or alcohol is used in the thermometer tube.

Question 3.
What do the figures on the scale indicate?
Answer:
The figures on the scale indicate temperature scale.

Question 4.
In which different units is the temperature measured?
Answer:
The temperature shows Celsius and Fahrenheit.

Question 5.
What season does the temperature in the figure indicate?
Answer:
The figure indicates summer season.

How will the rays fall between:

Question 1.
0° and 23° 30′ North and South?
Answer:
Perpendicular rays.

Question 2.
23° 30′ and 66° 30′ North and South?
Answer:
Slant rays.

Question 3.
66° 30′ and 90° North and South?
Answer:
Extreme slant rays.

What will you do?

You stay at ‘Man’ in Satara district. Your Grandma stays at Vengurla in Sindhudurg district. During Diwali, you often visit Vengurla. You like the sea coast there. The warm air of that region attracts you because you are freed from the dry air and scratching cold of your place. This time Grandma is suffering from asthma. Doctors have advised her to stay at a place which has a drier climate. What should you do?
Answer:

• Humid air is heavier than dry air, thus a person suffering from asthma finds it difficult to breathe in humid air.
• So, I will take my grandma to my place at Man’ in Satara district, as the air is dry in this region.

Think a little!

Question 1.
Will it be alright if water or oil is used in the thermometer?
Answer:
Water or oil cannot be used in a thermometer because they have a very high freezing part due to the lower temperature upto 30°C cannot be shown.

Question 2.
Where is the temperature of your district headquarters recorded?
Answer:
The temperature of the district headquarters is recorded in the district meteorological department.

Use your brain power!

Question 1.
Which season would be the best for visiting the following places and why? Goa, Chikhaldara, Chennai, Darjeeling, Ellora, Agra.
Answer:
Goa, Chennai, Ellora and Agra in the winter season. Chikhaldara and Darjeeling in the summer season.

Question 2.
Tell if the following statement is right or wrong. Give reasons.
In order to understand the climate of a region, the latitudinal extent is more useful than the longitudinal extent.
Answer:
The above statement is right.
In order to understand the climate of a region, the latitudinal extent is more useful because the earth is divided into three temperature zones depending on the amount of heat received from the equator to the North and South Poles.

Observe the map. Name the coastal areas that will experience changes in temperature. Give the reason for this.

Answer:
(i) West coast of North America : The California current moving from the Northern frigid zone to the torrid zone will reduce the temperature at this coast.

(ii) East coast of North America : The Gulf stream current flowing towards the northern frigid zone will increase the temperature at this coast.

(iii) West coast of Europe : The North Atlantic current flowing towards the Northern frigid zone will increase the temperature at this coast

Class 6 Geography Chapter 5 Temperature Additional Important Questions and Answers

Fill in the blanks wish the right alternative given in the bracket:

Question 1.
The main factor which influences the distribution of temperature is ______. (ocean current, longitude, latitude)
Answer:
latitude

Question 2.
______gas can hold heat within itself in the atmosphere. (Carbon dioxide, Oxygen, Hydrogen)
Answer:
Carbon dioxide

Question 3.
Isotherms are fairly parallel to the latitudinal line in the _____ hemisphere. (Northern, Western, Southern)
Answer:
Southern

Question 4.
Nagpur receives _______ climate. (extreme, equable, moderate)
Answer:
extreme

Question 5.
When an ocean current flows from the frigid to the torrid zone, it _____ the temperature of the coast in the torrid zone. (increase, reduces, equal)
Answer:
reduces

Question 6.
Isotherms are lines that connect places with the ______ temperature after avoiding the effect of the height, (different, same, moderate)
Answer:
same

Question 7.
Substance used in a thermometer tube is _____ (water, mercury, oil)
Answer:
mercury

Question 8.
The freezing point of mercury is _______°C. (-39, -49, -59)
Answer:
-39

Question 9.
The freezing point of alcohol is _____ °C. (-110, -120, -130)
Answer:
-130

Question 10.
Air temperature is measured in _______ (Celsius, Fahrenheit, Grams)
Answer:
Celsius

Match the pairs correctly:

Question 1.

Factor	Isoline
(1) Height	(a) Isotherm
(2) Temperature	(b) Isohyet
(3) Pressure	(c) Contour
(4) Rainfall	(d) Isobar
(5) Planktons	(e) Food for fishes
	(f) Ocean current

Answer:
1 – c
2 – a
3 – d
4 – b
5 – e

Give one word for the following sentences:

Question 1.
The sunrays which occupy less area.
Answer:
Perpendicular.

Question 2.
The sunrays which occupy larger area.
Answer:
Slant.

Question 3.
The climate in coastal areas.
Answer:
Equable.

Question 4.
The climate in continental areas.
Answer:
Extreme.

Question 5.
Food for fishes.
Answer:
Plankton.

Question 6.
Main factor responsible for influenceing the distribution of temperature.
Answer:
Latitude.

Question 7.
Measuring daily temperature.
Answer:
Thermometer.

Name the following:

Question 1.
Temperature zones on the earth:
Answer:
Torrid zone, temperate zone and frigid zone.

Question 2.
Lines drawn on a map by joining all the points having the same value:
Answer:
Isolines.

Question 3.
Two cold currents:
Answer:
Canaries and Peruvian current.

Question 4.
Two warm currents.:
Answer:
Equatorial and Brazil current.

Answer the following questions in one sentence each:

Question 1.
What is diurnal range of temperature?
Answer:
The difference in maximum and minimum temperature of a day is called diurnal range of temperature.

Question 2.
What factors leads to horizontal currents in the ocean?
Answer:
Horizontal currents develop in the ocean due

difference in temperature
density of water and
winds.

Question 3.
What is the advantage of the convergence of warm and cold current?
Answer:
The convergence of warm and cold current favours the growth of plankton.

Question 4.
What are isolines?
Answer:
Lines drawn on a map by joining all the points having the same value are called isolines.

Question 5.
Where is the distance between the isotherms parallel?
Answer:
The distance between the isotherms are parallel from South Pole to the Tropic of Capricorn.

Question 6.
Which factors lead to diversity in the climate of different regions?
Answer:
The factors which lead to diversity in the climate of different regions are nearness to the sea, continentality, height above the mean sea level and physical level.

Question 7.
What is an annual range of temperature?
Answer:
The difference in the mean temperatures of summer and winter is called an annual range of temperature.

Give geographical reasons for the following statements:

Question 1.
There is unequal distribution of heat received from the Sun.
Answer:
The unequal distribution of heat received from the Sun is because:

• The earth is spherical in shape.
• The rays which fall on the equator are straight, occupy less area and give more heat.
• The rays which fall on the curvature i.e., on the polar regions are slant rays which occupy large area and give less heat.

Question 2.
The temperature near the sea level is higher and it decreases in the mountainous region.
Answer:

• Firstly, the sea water gets heated by the rays of the sun.
• The absorbed heat is later radiated into the atmosphere.
• So, the layer of air close to the surface gets heated.
• This heat gets transferred vertically to the adjacent upper layers of air.
• Therefore, the temperature near the sea level is higher and it decreases at the mountainous region.

Question 3.
In the coastal areas, as compared to continental areas, the temperature of air is lower during the day but warmer at night.
Answer:

• There is difference in the heating and cooling of land and water.
• The air over the land gets heated faster and also cools rapidly.
• The air over the water gets heated slowly and also loses the heat in a slower manner.
• The temperature of air is lower during the day but warmer at night, in the coastal areas when compared to continental areas.

Question 4.
Greenhouse gases lead to increasing temperature of the earth.
Answer:

• Some gases in the atmosphere like carbon dioxide and water vapour can hold the heat within themselves for a long period of time.
• Due to the gases, the temperature of air in the atmosphere increases.
• Thus, greenhouse gases lead to increasing temperature of the earth.

Question 5.
Regions, where warm and cold currents converge, are favourable for the growth of fisheries.
Answer:

• Regions, where warm and cold currents converge, are favourable for the growth of planktons.
• Planktons are the food for fishes.
• Fishes travel here in large numbers.
• They breed in warm waters and increase the number of fishes.
• Therefore, regions where warm and cold currents converge favour the growth of fisheries.

Answer the following questions in short:

Question 1.
Explain the movement of ocean currents from equator to the polar region.
Answer:
Due to temperature differences, both upward and horizontal currents develop in the ocean. Besides temperature differences, factors like winds and differences in the density of water also give rise to horizontal currents. These ocean currents flow from the equator to the polar region and from the polar region to the equator.

Question 2.
Explain the effect of the ocean current flows from the frigid to the torrid zone.
Answer:
When an ocean current flows from the frigid to the torrid zone, it reduces the temperature of the coasts in the torrid zone. When a current flows from the torrid to the frigid zone, it increases the temperature of the coasts in the frigid zone.

I can do this!

Question 1.
Identify the temperature zones.
Answer:
There are three temperature zones namely torrid, temperate and frigid zones.

Question 2.
Tell the factors influencing temperature.
Answer:
Factors influencing temperature are latitude, winds, nearness to the sea, continentality, vegetation cover, cloud cover, physical set up, height above sea level and industrialisation.

Question 3.
Describe the global distribution of temperature with its characteristics.
Answer:
The isotherms in the southern hemisphere are fairly parallel to the latitudinal lines. From South Pole to the Tropic of Capricorn the distance between these lines is almost equal. As the proportion of land in the southern hemisphere is limited, temperatures in these parts are largely influenced by latitude.

In the northern hemisphere, the distance between these lines varies. In this hemisphere, the proportion of land is comparatively greater. This affects the distribution of temperature. These effects are seen in the form of variations in the distance between the isotherms and curved nature of these lines.

Question 4.
Describe the structure of a thermometer.
Answer:
A vacuum glass tube is filled with mercury or alcohol is mounted on a wooden board. There are two temperature scales showing Celsius and Fahrenheit.