Category: Class 8

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 16 Reflection of Light Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 8 Science Solutions Chapter 16 Reflection of Light

Class 8 Science Chapter 16 Reflection of Light Textbook Questions and Answers

1. Fill in the blanks:

Question i.
The perpendicular to the mirror at the point of incidence is called …………. .
Answer:
The perpendicular to the mirror at the point of incidence is called the normal.

Question ii.
The reflection of light from a wooden surface is ……….. reflection.
Answer:
The reflection of light from a wooden surface is irregular reflection.

Question iii.
The working of a kaleidoscope is based on the properties of …………… .
Answer:
The working of a kaleidoscope is based on the properties of reflection of light.

2. Draw a figure describing the following: The reflecting surfaces of two mirrors make an angle of 90° with each other. If a ray incident on one mirror has an angle of incidence of 30°, i draw the ray reflected from the second mirror. What will be its angle of reflection?

Question a.
Draw a figure describing the following: The reflecting surfaces of two mirrors make an angle of 90° with each other. If a ray incident on one mirror has an angle of incidence of 30°, draw the ray reflected from the second mirror. What will be its angle of reflection?
Answer:
For the ray C, the angle of reflection = 60°.

3. How will you explain the statement ‘We cannot see the objects in a dark room’?

Question a.
How will you explain the statement ‘We cannot see the objects in a dark room’?
Answer:
In a room that is completely dark, no light falls on objects. Hence, no light enters our eyes. Hence, there is no sensation of vision, i.e., we cannot see the objects.

4. Explain the difference between regular and irregular reflection of light.

Question a.
Explain the difference between regular and irregular reflection of light.
Answer:
For regular reflection of light, the angles of incidence as well as the angles of reflection are the same for all parallel rays of light incident on the plane and smooth surface. Hence, the reflected rays are also parallel to one another.

For irregular reflection of light, the angles of incidence for parallel rays of light incident on the rough surface are not equal, and hence the angles of reflection are also not equal. Here, the reflected rays are not parallel to one another and spread over a large surface.

5. Draw a figure showing the following:
(a) Incident ray, (b) Normal, (c) Angle of incidence, (d) Angle of reflection, (e) Point of incidence, (f) Reflected ray.

Question a.
Draw a figure showing the following:
(a) Incident ray
(b) Normal
(c) Angle of incidence
(d) Angle of reflection
(e) Point of incidence
(f) Reflected ray.
Answer:

6. Study the following incident.

Swara and Yash were looking in a water-filled vessel. They could see their images clearly in the still water. At that instant, Yash threw a stone in the water. Now their images were blurred. Swara could not understand the reason for the blurring of the images.
Explain the reason for blurring of the images to Swara by answering the following questions:

Question i.
Is there a relation between the reflection of light and the blurring of the images?
Answer:
Yes.

Question ii.
Which types of reflection of light can you notice from this?
Answer:
Regular reflection of light when light is incident on the still water and irregular reflection of light when light is incident on the water as ripples are produced on its surface when a stone is thrown in the water.
Still water behaves as a plane and smooth surface while oscillating water behaves as a rough surface.

Question iii.
Are the laws of reflection followed in these types of reflection?
Answer:
Yes.

7. Solve the following examples.

Question a.
If the angle between the plane mirror and the incident ray is 40°, what are the angles of incidence and reflection?
Solution:
The angle between the plane mirror and the incident ray is 40°. Therefore, the angle of incidence (i) = the angle made by the incident ray with the normal to the plane mirror = 90° – 40° = 50°. The angle of reflection, r – i – 50°.

Question b.
If the angle between the mirror and reflected ray is 23°, what is the angle of incidence of the incident ray?
Solution:
The angle between the mirror and the reflected ray is 23°. Therefore, the angle of reflection (r) = the angle made by the reflected ray with the normal to the plane mirror = 90° – 23° = 67°.
∴ The angle of incidence, i = r = 67°.

Project:

Question a.
Apollo astronauts who stepped on the moon have kept some large mirrors there. Collect information about how the distance to the moon is measured using these.

Class 8 Science Chapter 16 Reflection of Light Important Questions and Answers

Rewrite the following statements by selecting the correct option:

Question 1.
If the angle made by the incident ray with the surface of a plane mirror is 30°, the angle of reflection must be …….. .
(a) 30°
(b) 90°
(c) 60°
(d) 15°
Answer:
If the angle made by the incident ray with the surface of a plane mirror is 30°, the angle of reflection must be 60°.

Question 2.
If the angle of incidence is 40°, the angle made by the reflected ray with the surface of the plane mirror must be ……. .
(a) 40°
(b) 50°
(c) 20°
(d) 80°
Answer:
If the angle of incidence is 40°, the angle made by the reflected ray with the surface of the plane mirror must be 50°.

Question 3.
If the angle of incidence is 20°, the angle made by the reflected ray with the normal to the surface must be ……… .
(a) 20°
(b) 70°
(c) 10°
(d) 40°
Answer:
If the angle of incidence is 20°, the angle made by the reflected ray with the normal to the surface must be 20°.

Question 4.
In a kaleidoscope, the mirrors are inclined to each other at ……. .
(a) 60°
(b) 30°
(c) 45°
(d) 90°
Answer:
In a kaleidoscope, the mirrors are inclined to each other at 60°.

Question 5.
In a periscope, the mirrors are ………….. .
(a) parallel to each other
(b) at right angles to each other
(c) inclined at 45° to each other
(d) inclined at 60° to each other
Answer:
In a periscope, the mirrors are parallel to each other.

Find the odd one out and give the reason:

Question 1.
Plane mirror, Plywood, Wood, Rough tile.
Answer:
Plane mirror. In this case, regular reflection of light takes place. In other cases, reflection of light is irregular.

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

Question 1.
The sense of vision is the most important among our five senses.
Answer:
True.

Question 2.
In a periscope, the angle between the incident ray and the normal to the mirror is 30°.
Answer:
False. (In a periscope, the angle between the incident ray and the normal to the mirror is 45°.)

Answer the following questions in one sentence each:

Question 1.
What is an incident ray?
OR
Define incident ray.
Answer:
A ray of light falling on a surface is called an incident ray.

Question 2.
What is the point of incidence?
OR
Define point of incidence.
Answer:
The point at which the incident ray strikes the surface is called the point of incidence.
[Note: It is also the point of reflection.]

Question 3.
What is the normal?
OR
Define normal.
Answer:
The perpendicular to a surface at the point of incidence is called the normal.

Question 4.
What is the reflected ray?
OR
Define reflected ray.
Answer:
The ray of light that leaves the surface at the point of reflection (the same as the point of incidence) is called the reflected ray.

Question 5.
What is the angle of incidence?
OR
Define angle of incidence.
Answer:
The angle between the incident ray and the normal is called the angle of incidence.

Question 6.
What is the angle of reflection?
OR
Define angle of reflection.
Answer:
The angle between the reflected ray and the normal is called the angle of reflection.

Try this:

Switch off the light in your room at night for some time and then turn it on again.

Question 1.
Could you see the objects in the room clearly when the light was switched off?
Ans.
No.

Question 2.
What did you feel when it was turned on again?
Answer:
We could see the objects clearly. From the above activity you can notice that there is some connection between the sense of vision and light. When we switch off the light at night, the objects in the room cannot be seen and they can be seen as before when the light is switched on again. Thus, we can see objects when the light coming from these objects enters our eyes.

Answer the following questions:

Question 1.
What is reflection of light?
Answer:
When light rays fall on an object, their direction changes and they turn back. This is called the reflection of light.

Try this:

Material:
Torch light, mirror, a stand for hanging the mirror, black paper, comb, white paper, drawing board.
Activity :
1. Fit a white paper tightly over a table or drawing board.
2. Leaving out some portion in the middle of the comb, cover the rest with black paper so that light can only pass through the open central portion.
3. Hold the comb perpendicular to the white paper and throw torch light on its central portion.
4. Adjust the comb and torch so as to get light rays on the white paper. Now keep a mirror in the path of this ray of light as shown in the figure.
5. What do you observe?

Answer:
Light rays which fall on the mirror get reflected and travel in a different direction.

Question 2.
State the laws of reflection of light.
Answer:

1. The angle of reflection is equal to the angle of incidence.
2. The incident ray, the reflected ray and the normal lie in the same plane.
3. The incident ray and the reflected ray are on the opposite sides of the normal.

Try this:

Verification of the laws of reflection of light.
Equipment: Mirror, drawing board, pins, white paper, protractor, scale, pencil.
Activity:

1. Fit a white paper on the drawing board tightly as possible.
2. On the paper draw a line PQ indicating the position of the mirror.
3. Draw a perpendicular ON to PQ at point O.
4. Draw a ray AO making an angle of 30° with ON.
5. Fix two pins S and R along AO.
6. Fix the mirror to a stand and place it along PQ perpendicular to the drawing board.
7. Fix pins at T and U along the line joining the bottom of the reflected images of the pins at S and R.
8. Remove the mirror and join the points T and U and extend it up to O.
9. Measure ZTON.
10. Repeat steps 4 to 9 for angle of incidence equal to 45° and 60° and write down the angles in the following table.

What relation do you find between the angle of incidence and the angle of reflection? If you have done the experiment carefully, you will find that the angle of incidence is equal to the angle of reflection in all three cases. This verifies the laws of reflection.

Question a.
What will happen when a light ray is incident perpendicular to the mirror?
Answer:

Here,
r = i = 90°.
Hence the light ray, on reflection, will retrace the path.

Question 3.
Figures (a) and (b) show three parallel rays, shown in grey, incident on smooth and rough surfaces. The reflected rays drawn using laws of reflection are shown in red.
1. Rays reflected from which surface are parallel to one another?
2. What conclusion can you draw from the figure?
Answer:
1. Rays reflected from the smooth surface are parallel to one another.

2.When the reflecting surface is plane and smooth, the angles of incidence (i) as well as of reflection (r) are the same for all parallel rays incident on the surface. If i₁, i₂, i₃, … are the angles of incidence for incident parallel rays, and r₁, r₂, r₃, …, are the corresponding angles of reflection, then, i₁ = i₂ = i₃ = ……. = r₁ = r₂ = r₃ = ….. This is called regular reflection. Here, the reflected rays are parallel to one another. If the reflecting surface is rough and parallel rays are incident on it, then the angles of incidence are not equal and hence the angles of reflection are also not equal. Here, i₁ ≠ i₂ ≠ i₃ … and r₁ ≠ r₂ ≠ r₃ …, but r₁ = i₁, r₂ = i₂, r₃ = i₃ … as laws of reflection are obeyed. This is called irregular reflection. [Fig.(b)]. Here, the reflected rays are not parallel to one another and spread over a large surface.

Question 4.
What is regular reflection of light?
Answer:
The reflection of light from a plane and smooth surface is called regular reflection of light.

Question 5.
What is irregular reflection of light?
Answer:
The reflection of light from a rough surface is called irregular reflection of light.

Always remember:

1. Laws of reflection are followed in both and regular and irregular reflection.
2. The reflection of light in irregular reflection has not been obtained because the laws of reflection are not followed. They are obtained because the surface is rough (irregular).
3. In irregular reflection, the angles of incidence at different points are different. But at any one point, the angles of incidence and reflection are equal, i.e. i₁ = r₁, i₂ = r₂ …..

Can you recall?

Reflection of reflected light :

Question 1.
How do you see if the barber m a saloon has cut the hair on your neck properly or not?
Answer:
In a saloon, there are mirrors in your front and at back. The image of the back of your head is formed in the mirror at the back. The image of this image is formed in the mirror in front of you. Thus you can see how the hair at the backside of your head is cut.

Question 2.
What type of image do we see in a mirror? What happens to the left and right sides?
Answer:
The image in a plane mirror is upright (erect) and of the same size as the object, but the left and right sides are interchanged. Our right hand appears to be the left hand in the image and the left hand appears to be the right hand in the image. (This is called lateral inversion.)

Question 3.
How do we see the image of the moon in water?
Answer:
The moon is not self luminous. The sunlight falling on the surface of the moon is reflected. This reflected light is again reflected by water to give us the image of the moon.

Try this:

Kaleidoscope:

Activity:

1. Take three rectangular mirrors of the same size.
2. Using sticking tape, stick the mirrors together making a triangle with the reflecting surface facing inwards (see Fig.).
3. Take a white paper of triangular shape and fix it with a tape at one end of the mirrors closing that end.
4. Insert 4 – 5 coloured glass pieces in the hollow of the mirrors.
5. Close the other end also with a paper and make a hole in it.
6. Look through the hole towards light. You will see innumerable images of the glass pieces. These are formed due to reflections by the three mirrors.

You can see different designs in the kaleidoscope. The speciality of a kaleidoscope is that the designs do not easily repeat themselves. Every time the design is different. People making wall papers which are used to decorate walls and cloth designers use a kaleidoscope for making new designs.

Periscope:
Activity:

1. Take a cardboard box. Make slits in the top and bottom sides of the box and place two mirrors so that they make an angle of 45° with the sides of the box and are parallel to each other. Fix them with a sticking tape.
2. Make two windows of 1 inch each near the two mirrors. Now see through the bottom window.
3. Make note of what you see.

From the bottom window, one can see what is in front of the top window. This device is called a periscope. This is used in submarines to see objects above the surface of water. It is also used to observe and keep a watch on the objects or persons on the ground from an underground bunker. The kaleidoscope and periscope both use the properties of reflection of light.

[Note: In a periscope, the angle of incidence is 45° and the two plane mirrors are parallel to each other. Hence, the emergent ray is parallel to the incident ray.]

Example questions for practice:

Question 1.
If the angle between the plane mirror and the incident ray is 20°, what is the angle between the reflected ray
and the plane mirror?
Answer:
20°.

Question 2.
See Fig. In terms of O, what are the angles (i) AON (ii) BON (iii) AOB (iv) BOQ?

Answer:
(i) 90° – θ (ii) 90° – θ (iii) 180° – 2θ

Balbharti Maharashtra State Board Class 8 English Solutions Chapter 2.3 The Worm Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 8 English Solutions Chapter 2.3 The Worm

Class 8 English Chapter 2.3 The Worm Textbook Questions and Answers

Warming Up:

1. ‘Worms play a very important role; in maintaining ecological balance. They are friends of farmers.’ Form groups and discuss the significance; of worms in the above two roles.
(Point: worms – loosen the soil-bring up fertile soil-turn organic garbage into organic fertilizers-provide/proteins, etc.)
(Students can discuss this as Oral Work.)

2. Think and write down how the following creatures can be useful:

Question a.
DragonFly:
Answer:
eats mosquitoes and flies; controls unwanted insects.

Question b.
Spider:
Answer:
keeps insect population under control.

Question c.
Ants:
Answer:
turn and aerate the soil; help; in seed dispersal.

Question d.
Honeybees:
Answer:
provide honey; help in pollination.

Question e.
Earthworms:
Answer:
loosen the soil; turn organic garbage into fertilizer.

3. Little creatures in nature can also be your teachers. Think and write: what we can learn from the following:

Question a.
Bees:
Answer:
organization; hard work self-sacrifice

Question b.
Ants:
Answer:
team work hard work discipline

Question c.
Spiders:
Answer:
patience perseverance

Question d.
Caterpillars:
Answer:
patience acceptance of change

4. Breeding worms to convert organic waste into fertilizer is called Vermiculture or Vermicomposting.
Find out more about Vermiculture and how you can carry out the same in your garden/backyard to fertilize your plants at home.
(Students can attempt this on their own as a project.)

1. Read the poem aloud and you ill find some old outdated words that we do not use in everyday language now.
However, some writers poets use them to impart an old-fashioned flavour to suit the background of their write-up. Such words are called Archaic words.
Give the modem words for the archaic words from the poem.

1. thy
2. being
3. bestow’d
4. thee
5. thou
6. canst

Answer:

1. thy – your
2. being – life
3. bestow’d – gifted/given as a gift
4. thee – you
5. thou – you
6. cans’t – can

Read any poem I sonnet by William Shakespeare. Pick out archaic words and guess what they mean.

2. The poet uses a device where he directly addresses someone absent or abstarct. Such a device is the Figure of Speech called ‘Apostrophe’.
For example: Turn, turn, thy, hasty, foot aside.

Pick out any two other lines from the poem that on1uin an Apostrophe.
Answer:
(i)Turn, turn thy hasty foot aside
(ii) Let them enjoy their little day
(iii) O do not lightly take away
The life thou canst not give.

3. Think and answer in your own words ¡n your notebook:

Question a.
Why does the poet appeal to us to respect the life of worms?
OR
Why should we take care even of small worms?
Answer:
The poet urges us to remember that every creature on this earth is created by God for some purpose. We must hence respect every creature, big or small, for each has its own role to play in this universe. Besides, we have no right to lightly take away a life which we cannot give back.

Question b.
Why had God created worms? What is their ecological importance?
Answer:
Every creature on this earth is created by God for some purpose. Worms play a very important role in maintaining ecological balance. They loosen and aerate the mud and bring up fertile, nutrient-rich soil. They turn organic garbage into organic fertilizers. Their bodies provide proteins.
Thus, though they are so small, they play a huge role in maintaining ecological balance, and this is the purpose for which God created them.

Question c.
Live and let live’ is a famous proverb. Which lines from the poem support this proverb?
Answer:
The lines from the poem that support the proverb ‘Live and let live’ Eire:

(i) Turn, turn thy hasty foot aside Nor crush that helpless worm
(ii) Let them enjoy their little day
(iii) Do not lightly take away The life thou canst not give

Question d.
Does the poem urge us to protect I only worms ? What is the general message conveyed through the poem?
Answer:
Though the poem is about the worm, the general message is that God has created all the creatures on earth, big ? and small, and every creature has a role to play. All beings have equal rights over the bounties of the earth. No one can take away a life that he/she cannot give.

4. Find from the library or internet other poems composed on tiny Hing creatures. Try to understand the message in each of them.

5. ‘Even small things in nature play a big role. So protect nature!’
Frame some solgans based on the above topic.
Draft a short speech on the abose topic, which you could give at your school assembly.
Use the following steps while drafting.
(1) Greeting
(2) Salutation
(3) Self-introduction
(4) Introduction of the topic
(5) Body of the speech
(6) Conclusion
(7) Expression of gratitude to audience
Answer:

Small But Important

Respected Principal, teachers and my dear friends, Good morning. Today is 5th June, World Environment Day, and on this important day I, Smruti Kamath, would like to say a few words on the huge role played by the small things in nature.

Let me begin with the earthworm. The earthworm is rightly called the friend of the farmer for it helps the farmer in immeasurable ways. It not only loosens and turns up the soil, it converts garbage into organic fertilizer too. Those minute creatures, ants, help in aerating the soil and in seed dispersal. Bees, in addition to providing honey, are indispensable in pollination. We owe our food to the work done by these little insects. Dragonflies and spiders keep down the insect population by eating insects. Frogs and fish eat the larvae of mosquitoes.

I could go on and on, extolling the virtues and the uses of every little being on this earth. However, time does not permit me to do this, and I end my speech by requesting all of you here to understand and respect the importance and the place of every little creature on this earth. Thank you.

6. Puruphrase the poem in your own simple language. Write it down in your notebook.
Answer:
In this poem, the poet tells the reader, who is in a hurry, to turn his foot aside so that he does not crush the helpless worm. The reader may be filled with scorn and hatred for the worm, but it was created by God.

The same God who made human beings and all other things that move has also given a portion of His unlimited love to the poor worm.
God has given the sun, the moon and the stars free to all the creatures He created. The grass that grows over the earth was made for worms as well as for human beings. The poet urges the reader to allow the worms to enjoy their brief life with its humble pleasures. He tells us not to take away a life which we cannot give.

7. Frame a pointwise Analysis of the poem ‘The worm’. Use the following points.
Answer:

(a) Poem and poet: ‘The Worm’ by Thomas Gisborne.
(b) Theme: Respect every creature big or small, for each has its own role to play in this universe.
(c) Tone: Serious and thought-provoking in the imperative.
(d) Structure and stanzas: Stanzas of four lines each short lines.
(e) Rhyme and Rhythm: Rhyme scheme: abab, cdcd, and so on. The last words of the first and third line and second and fourth line of every stanza rhyme, Rhythm is smooth.
(f) Language and Imagery: Archaic language; no imagery.
(g) Figures of Speech: Apostrophe, Inversion.

Class 8 English Chapter 2.3 The Worm Additional Important Questions and Answers

Complete the following:

Question 1.
The other creations of God that are mentioned in the poem are the sun, _____.
Answer:
the moon, the stars, the earth, blades of grass and humans.

Question 2.
The thought in the last two lines is that _____.
Answer:
we have no right to lightly take away a life that we cannot give back.

Question 3.
Pick out examples of Inversion from the poem.
Answer:
(i) On that poor worm bestow’d
(ii) The sun, the moon the stars He made To all His creatures free.

Writing Skills:

Question 1.
Even small things in nature play a big role. So protect nature Frame some slogans based on the above topic.
Answer:
(i) Nurture nature and get/nurtured by nature.
(ii) All creatures great and small.
The good Lord made them all.
(iii) Take care of one and all.
All creatures great and small.

Balbharti Maharashtra State Board Class 8 English Solutions Chapter 1.2 Dick Whittington and his Cat Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 8 English Solutions Chapter 1.2 Dick Whittington and his Cat

Class 8 English Chapter 1.2 Dick Whittington and his Cat Textbook Questions and Answers

Warming Up:

1. Discuss the follow in groups and write the answers:

Question a.
Name the world famous personalities, who reached great heights despite of humble circumstances.
Answer:

• Dr. A.P.J. Abdul Abraham
• Lincoln Kalam
• Charlie Chaplin
• Kalpana Chawla

Question b.
Guess the types of hardships they must have faced in their childhood and youth.
Answer:

• poverty
•  lack of support
• social disapproval
• lack of opportunities

Question c.
What strong qualities possessed by them, could have helped them achieve success and fame, all over?
Answer:

• strong will power
• optimism
• sincerity
• hard work

Question d.
How do stories / biographies of such famous people help youngsters?
Answer:

• They help youngsters to look at life positively.
• They inspire the youth.
• They help them find answers to questions.
• They prove that we can do many seemingly impossible things if we really wish to.

2. Syllable: A syllable is a unit of pronunciation that has one ‘owe1 sound and may or may not have consonant sounds before I after it.
Examples of words having:
One syllable: a, I, see, at, on, man, with, thread
Two syllables: mother, seated, giraffe, parrot, active, happy
Three syllables: happiness, wonderful, animal, surprising, adventure, ignorance.
More than three syllables: consequently, encouragement, responsibility, identifying, encyclopedia

Write the numcs of any 5 of your classmates and list how many syllables each name has.
Answer:

• Jal: 1 syllable
• Remo: 2 syllables
• Saira: 2 syllables
• Shailaja : 3 syllables
• Mandakini: 4 syllables
• Ali: 2 syllables

1. A. Arrange the following set of words in alphabetical order in your notebook.
ship, small, successful, scoldings, stone, saving, someone, stood, streets, still, screamed, sot, seemed, saint, share.
Answer:
saint, sat, saving, scoldings, screamed, seemed, share, ship, small, someone, still, stone, stood, streets, successful.

1. B. Remove the Affixes (Prefix and Suffix) and write the Root-word.

1. successful
2. immediately
3. retrace
4. mouser
5. unfriendly
6. fallen
7. unkind
8. wooden
9. luckily
10. belonging

Answer:

1. success
2. immediate
3. trace
4. mouse
5. friendly
6. fall
7. kind
8. wood
9. luck
10. belong

2. A. Find from the story’ one word for the following.

Question a.
a small room just below a sloping roof
Answer:
attic

Question b.
a very narrow passage between buildings
Answer:
alley

Question c.
the highest – ranking officer in the Municipality of a city/town.
Answer:
Mayor

Question d.
the highest ranking official who commands a ship.
Answer:
Captain

Question e.
any animal that catches mice
Answer:
mouser

Question f.
a low constant sound made by cats
Answer:
Purr

2. B. Make sentences of your own using the following expressions.

Question 1.
overcome:
Answer:
We must learn to overcome any difilcultics we come across.

Question 2.
put up with:
Answer:
We had to put up wilhi the noisy behaviour of our neighbours son.

Question 3.
bargain:
Answer:
People In India love to bargain with hawkers.

3. Rearrange the following events us they occur in the story. Put the correct number in the boxes.

Answer:

4. Think and answer:

Question 1.
What decision taken by Dick changed his fortune?
Answer:
On hearing the church bells send out a message to him, Dick decided to retrace his steps and go back to Mr. Fitzwarren’s house instead of running away. This decision changed Dick’s fortune.

Question 2.
What message does this story bring j out for youngsters?
Answer:
The message that this story brings out for youngsters is that we must S not run away from difficulties but face > them bravely.

5. A. Break the words below into syllables us shown in the first one.

1. belonging
2. morning
3. unfriendly
4. citizen
5. anything
6. message
7. difficulty
8. mayor
9. captain
10. elected

Answer:

1. be – long – ing
2. mor – ning
3. un – friend – ly
4. ci – ti – zen
5. an – y – thing
6. mess – age
7. di – ffi – cul- ty
8. ma – yor
9. cap – tain
10. e – lec – ted

5. B. Degrees of Comparison of Adjectives.

Read the sentences.

(i) Yatin is strong.
(ii) Amit is stronger than Yatin.
(iii) Pruvin is the strongest of all.

In sentence (i) the Adjective ‘strong’ is in its simple form. It is called Positive Degree.
In sentence (ii) the Adjective stronger’ refers to a higher degree, when there is a comparison of two nouns. It is called Comparative Degree. (-er is
added to the basic Adjective)
In sentence (iii) the adjective ‘strongest’ refers to the highest degree of comparison of one with more than two nouns. It is called Superlative
Degree. (-est is added to the basic Adjective)

Complete the table of degrees of comparison.

Answer:

Positive	Compa­rative	Super­lative
(1) great	greater	greatest
(2) famous	more famous	most famous
(3) easy	easier	easiest
(4) bad	worse	worst
(5) poor	poorer	poorest
(6) lazy	lazier	laziest
(7) little	less	least
(8) worthy	worthier	worthiest
(9) popular	more popular	most popular

6. Select any one of the famous personalities mentioned in ‘Warming up 1′ on page no. 5. From the library or internet find out their success story. Write ¡tin your own words in about 20 to 30 lines of your notebook. Give your write-up a suitable title.

Class 8 English Chapter 1.2 Dick Whittington and his Cat Additional Important Questions and Answers

Simple Factual Activities :

Complete the following :

Question 1.
Dick lived in a ______.
Answer:
small village in the south of England

Question 2.
_____ treated Dick unkindly.
Answer:
Many of the villagers

Question 3.
The innocent belief ________.
Answer:
that the streets of London were paved with gold made Dick decide to go to London

Question 4.
The carter asked Dick _______.
Answer:
if he was running away from home

Complex Factual Activity:

Question 1.
Describe the hardships that Dick I faced on arriving in London.
Answer:
Dick arrived in London just before ; nightfall. He had no place to sleep, and he finally slept in the corner of a narrow lane. The following morning, Dick woke ( up feeling cold, miserable and hungry. He j begged for food, but people shouted at him | and hit him angrily on his head. He finally collapsed and lay there, too weak to look further for food.

Activities based on Contextual Grammar:

Question 1.
He thought people might treat him more kindly if he were rich. (Identify the modal auxiliary and state its function.)
Answer:
might-indicates possibility

Question 2.
All he could see were dirty streets and lots of unfriendly people.
(Rewrite using ‘nothing’.)
Answer:
He could see nothing but dirty streets and lots of unfriendly people.

Personal Response:

When Dick begged for food, people shouted at him and beat him. Do you think this is right?
Answer:
of course it is not right. We ; should have sympathy when people beg for something, not get angry with them. They must be having a strong reason for begging, of course, if they are lazy, do not work and then beg, it is wrong. Even then, we must not beat them or shout at them.

Complete the following:

Question 1.
Mr. Fitzwarren favoured Dick by ______.
Answer:
ordering the cook to take him into the kitchen, feed him and then find some work for him

Question 2.
Dick had to face two difficulties in Mr. Fitzwarren’s house. They were:
Answer:
(i) the attic where he slept was overrun by rats and mice, preventing him from sleeping.
(ii) the cook was bad-tempered and shouted and screamed at Dick, scolding him and hitting him with a wooden spoon even when he was working as hard as he could.

Question 3.
The cat proved to be very useful because _____.
Answer:
it chased away all the rats and mice, allowing Dick to sleep peacefully

Activities based on Contextual Grammar:

Question 1.
Dick had fallen in front of a house belonging to a rich merchant. (Rewrite using the simple past tense of the underlined verb.)
Answer:
Dick fell in front of a house belonging to a rich merchant.

Question 2.
Dick was able to sleep peacefully.
(Rewrite using the verb ‘slept’.)
Answer:
Dick slept peacefully.

Personal Response:

Question 1.
What do Mr. Fitzwarren’s actions tell us about him?
Answer:
Mr. Fitzwarren’s actions tell us that he was a kind-hearted and just man.
He did not abuse Dick or hit him as the others had done. He offered Dick a home and a living in return for helping the cook with all the pots and pans in the kitchen.

Simple Factual Activities:

Who said the following words:

Question 1.
I can put up with a few scoldings from the cook.
Answer:
Dick

Question 2.
No, it must be his.
Answer:
Mr. Fitzwarren

Question 3.
Only my cat.
Answer:
Dick

Question 4.
Let me put something in for him.
Answer:
Alice

Fill in the blanks:

Question 1.
Dick walked as far as ________.
Answer:
Holloway

Question 2.
The first of November is _______.
Answer:
All Saints’ Day

Question 3.
Dick went back to _____.
Answer:
Mr. Fitzwarren’s house

Question 4.
Mr. Fitzwarren was sending a ship to the _____ to trade.
Answer:
African coast

Complex Factual Activity:

Question 1.
’“Explain in your own words what inspired Dick to return to Mr. Fitzwarren’s home.
Answer:
When Dick sat down on a stone to rest, he heard the church bells ringing. As he listened, it seemed that they were ringing a message for him, telling him that he should go back home, and calling him the Mayor of London.

Pick out the subject and predicate in the following sentences and put them in the correct columns in the table given below :

1. You can then share in the profits.
2. Everyone produced something except for Dick.
3. The two of them walked as far as Holloway.
4. Dick and his cat retraced their steps to Mr. Fitzwarren’s house.

Answer:

Subject	Predicate
(1) You	can then share in the profits
(2) Everyone	produced something except for Dick
(3) The two of them	walked as far as Holloway
(4) Dick and his cat	retraced their steps to Mr. Fitzwarren’s house.

Personal Response:

Question 1.
According to you, did Dick do the right thing by running away from Mr. Fitzwarren’s house because of the cook?
Answer:
No, I don’t think that Dick did the right thing. Mr. Fitzwarren was a good man, and Dick was making a decent living. He should have tried to win the cook over and solve his difficulties. If he had run away, he may not have got another job and may have had to beg. Nothing is gained by running away from problems; we must face them and solve them.

Write whether the following statements are True or False:

Question 1.
Dick was happy to send his cat on the ship.
Answer:
False

Question 2.
The cat caught plenty of mice and rats.
Answer:
True

Question 3.
The king was rude to the captain.
Answer:
False

Question 4.
The queen knew all about cats.
Answer:
False

Pick out two adverbs ending in ‘-ly’ from the passage, and write the adjectives in them.
Answer:
Adverbs-immediately, normally, Adjectives in them-immediate, normal

Personal Response:

Do you think that all the animals are 1 important to the environment?
Answer:
Yes, all the animals are certainly j important to the environment. They all have their own place and own duties. ; For example, hawks and eagles control the population of mice, rats and snakes. Lions and tigers keep the number of deer, buffaloes and other such animals in check, j Every animal is important in its own way.

Write the following sentences in the correct order of occurrence in the passage:

1. Dick was knighted by the king and became Sir Richard Whittington.
2. Dick was elected the Mayor of London.
3. The king paid ten times the sum for the cat.
4. “I would give great wealth to own this animal,” said the queen.

Answer:

1. “I would give great wealth to own this animal,” said the queen.
2. The king paid ten times the sum for the cat.
3. Dick was elected the Mayor of London.
4. Dick was knighted by the king and became Sir Richard Whittington.

Give reasons:

Question 1.
The queen was afraid of the cat.
Answer:
The queen was afraid of the cat because she had seen how fiercely it had attacked the rats and the mice.

Question 2.
How much did the king pay for the cat?
Answer:
The king paid ten times the sum for the cat that he had paid for the whole cargo from Mr. Fitzwarren’s ship.

Activities based on Contextual Grammar :

Pick out the verbs from the following sentences and state their tense :

Question 1.
The captain showed Mr. Fitzwarren the gold and jewels he had brought from Barbary.
Mr. Fitzwarren then paid him all: the money he had received for the cat.
Answer:
showed – simple past tense; had brought – past perfect tense
paid – simple past tense; had received – past perfect tense

Personal Response:

Question 1.
What message does this story bring j out for youngsters?
Answer:
The message that this story brings out for youngsters is that we must S not run away from difficulties but face > them bravely.

Do as directed:

Question 1.
Pick out two compound words from the lesson.
Answer:
Two compound words : household, nightfall

Question 2.
Use the adverb ’immediately’ in your own sentence :
Answer:
The teacher immediately asked the tired girl to sit down.

Question 3.
Find out four hidden words from : the given word : (Each word should have at least 3 letters.)
successful
Answer:
successful : success, self, fuel, fuse

Question 4.
Use the following word and its homophone in two separate sentences :ate
Answer:

• The little boy ate the cake very quickly,
• He was eight years old when he got a new cycle.

Question 5.
Underline the adjectives from the following sentence :
He was not only famous, but he was popular too, for he always helped the poor ; with his money.
Answer:
He was not only famous, but he was popular too, for he always helped the poor with his money.

Question 6.
Pick out the conjunction in the following sentence :
Dick work up cold, miserable and very hungry.
Answer:
and

Question 7.
Punctuate :
alas yes came the reply the country is suffering from a plague of rats and mice
Answer:
“Alas, yes!” came the reply. “The country is suffering from a plague of rats and mice.”

Question 8.
Pick out the direct and indirect objects:
He gave me a hundred rupee note.
Answer:
Direct object – a hundred-rupee note
Indirect object – me

Question 9.
Use the following word as a noun and a verb in two separate sentences :
sleep
Answer:

• We should get at least 8 hours of sleep daily, (noun)
• I sleep at 10 pm daily, (verb)

Balbharti Maharashtra State Board Class 8 English Solutions Chapter 1.4 Revathi’s Musical Plants Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 8 English Solutions Chapter 1.4 Revathi’s Musical Plants

Class 8 English Chapter 1.4 Revathi’s Musical Plants Textbook Questions and Answers

Warming Up

1. Discuss in groups and share your answers with the class:

Question 1.
Can you name the famous musician in Emperor Akbar’s court, who could perform miracles, when he sang different Ragas?
Answer:
Tansen

Question 2.
What miracles could he perform with his music?
Answer:
It is said that Tansen could create rain and fire just through his music. If he sang the Raga Deepak, the area around ; him would catch fire. If he sang Megha ; Malhar, it would begin to rain. If he sang an evening raga during daytime, the sunlight i would diminish and it would look like it j was dusk already.

Question 3.
What impact does music have on ! human beings?
Answer:
Music can make human beings happy, sad, nostalgic, mournful, etc. It can soothe them when they are stressed. It can also convey a lot of emotions like love, anger, etc. that may not be conveyed easily through words.

Question 4.
Do you think that music can have an impact on animals, birds and even | plants?
Answer:
Yes, definitely. It has already been proved by Jagdish Chandra Bose that plants respond to music. It is said that cows give more milk if they listen to good music. Our folklore is full of instances of snakes swaying to the music played by snake charmers.

2. Affirmative and Negative sentences:

Read the sentences below and spot the difference in their framing:
1. (a) I could not complete the work.
(b) I failed to complete the work.

2. (a) There is no sense in what you say.
(b) There is hardly any sense in what you say.

3. (a) He said he wouldn’t go.
(b) He refused to go.

You will observe that sentences marked (a) and (b) convey the same meaning. But in all sentences marked (a) there are negative words (no, not, wouldn’t) whereas the ones marked (b) do not have them.
Negative words are those that convey a negative meaning.
For example: never, no, neither, nor, not, cannot, don’t, isn’t, nothing etc.
If a sentence contains Negative words, it is called a Negative Sentence.
If a sentence does not contain any Negative word, it is called Affirmative sentence.

Note: While interchanging Negative and Affirmative sentence, the meaning and tense must not change.
You must use Negative words in the sentence, while transforming from Affirmative to Negative.
You may use words like hardly I fail to I refuse / reject / avoid / prohibit / without / ban etc., while changing Negative sentences to Affirmative.

Say whether the following sentences are Affirmative or Negative ones:

Question 1.
We must avoid hurting others.
Answer:
Affirmative

Question 2.
She didn’t offer me any help.
Answer:
Negative

Question 3.
Never give up hope.
Answer:
Negative

Question 4.
You must keep away from bad company.
Answer:
Affirmative

Question 5.
There is nothing in the bag.
Answer:
Negative

Question 6.
Entry is prohibited, without permission.
Answer:
Affirmative

1. Read the story and complete the following:

Question a.
At first, Revathi’s plants did not look normal and healthy because of _______.
Answer:
they had pale green leaves and their growth was stunted due to insufficient sunlight.

Question b.
When Revathi played her favourite raga, the plants began to move because _____.
Answer:
they liked the music she was playing.

Question c.
Revathi’s grief knew no bounds because _________.
Answer:
she could not find her pot of balsam plants.

Question d.
Revathi was confident of proving her ownership of her pot of plants because________.
Answer:
she knew that her plants loved music and would respond to her favorite raga. They would bend their stems towards her, proving that they were hers.

Question e.
Revathi won the prize for the ‘Best Plant’ because of ______.
Answer:
her plants were the best looking and the healthiest.

2. Answer in your own words:

Question a.
What did Revathi discover about her balsam plants?
Answer:
Revathi discovered that her balsam plants were not only taller and healthier than the other balsam plants, but they had started flowering earlier too. The flowers were big and brightly coloured, and one of the plants had an unusual kind of flower. She also discovered that while the plants liked her favourite tune, they did not like the tune with a quick rhythm.

Question b.
Why did Revathi decide to keep her new knowledge ‘a secret’?
Answer:
Revathi decided to keep her new knowledge a secret perhaps because she felt that it was something only between her and her beloved plants, whom she considered her friends. or perhaps she felt that nobody would believe her if she mentioned that her plants were music lovers.

Question c.
How did the plants respond when Revathi played her favourite tune?
Answer:
When Revathi played her favourite tune on her violin, the plants all bent their stems towards her even though there was no breeze.

Question d.
How did the plants react to the fast rhythmic music?
Answer:
When Revathi played a tune with a quick rhythm, the plants turned away from her as though they did not like what she was playing.

Question e.
How did Revathi prove to the organisers of the competition that the plants truly belonged to her?
Answer:
When Revathi played her favourite tune, the plants bent their stems towards her as though they wanted to touch her in their happiness. This convinced the organisers that the plants were hers.

Question f.
What helped Revathi to claim her plants her belief in magic or the belief in her convictions? Explain your choice.
Answer:
Her belief in her convictions helped Revathi to claim her plants. She was sure that her plants were music lovers and would respond to her favourite raga as they had done before. There was no magic involved. It was a fact.

3. A. An ord chain consists of words of a certain category that begin with the letter, that the previous word has ended with.
Complete the word chain adding Four Nouns from the text.
Music → courtyard → ………
Answer:
music → courtyard → days → surprise → evening → grief.

3. B. Add the appropriate Prefix to make the following words opposite in meaning.

1. continue
2. possible
3. certain
4. definite
5. believe
6. important
7. place
8. known
9. regular

Answer:

1. Discontinue
2. Impossible
3. Uncertain
4. Indefinite
5. Disbelieve
6. Unimportant
7. Displace/Misplace
8. Unknown
9. Irregular

3. C. Use the following expressions to make sentences of your own:

Question 1.
make up one’s mind
Answer:
make up one’s mind – One should think carefully before one makes up one’s mind about anything important.

Question 2.
struck as odd
Answer:
struck as odd: My friend’s continuous laughter on seeing her marks struck me as odd.

Question 3.
knew no bounds
Answer:
knew no bounds: My joy knew no bounds when I saw the little puppy on my bed.

Question 4.
flash across one’s mind
Answer:
Flash across one’s mind: When Sonam saw the tears in Dia’s eyes, it flashed across her mind that there was some problem.

Question 5.
to surmise
Answer:
to surmise: When the teacher saw Naomi crying, she surmised that she had failed ¡n the test.

Question 6.
not to deter
Answer:
not to deter: The loss of a leg did not deter Sudha Chandran from dancing.

4. Imagine there is a ‘Best Plant’ Competition in the locality /colony where you live. Frame a Notice about the same, in the form of an attracti’e poster.
Cover the following points.

Name of the organisation.
Name of the Contest.
Day, Date, Venue.
Who can participate.
Prizes.
Contact details for further enquiry.
Answer:

5. Types of sentences:

Study the following sentences.
Set (A)
Revathi was a student of music.
The flowers were big and brightly coloured; indeed.
They were requested to believe her.
All the above sentences are statements or assertions, and called Assertie or Declarative sentences.

Set (B)
Wasn’t Revathi a student of music?
How can we doubt her?
Do plants have ears?
The above sentences in Set (B) are Questions. They are called Interrogatie sentences.

Set (C)
Please believe me.
Let us rutch the fun.
Sit straight.
Excuse me.
In Set (C) the sentences are either requests, appeals, commands, suggestions etc. Such sentences are called Imperative Sentences.

Set (D)
How big and bright the flowers were!
What a surprise!
Ah, what beautiful music that is!
Set (D) has sentences that express strong feelings. They are called Exclamatory Sentences

State the kinds of the following sentences:

• How happily she played the violin!
• They all bent towards her.
• Don’t play that quick tune.
• She kept the knowledge a secret.
• How can plants enjoy music?
• How proudly did Revathi carry home her prize!
  What could have token my plants?
• The organisers were not convinced.

6. Make the following Negative using the negative words given:

Question 1.
There were a few potted plants in the courtyard. (not many)
Answer:
There were not many potted plants in the courtyard.

Question 2.
They looked healthier than the other plants. (not as healthy as)
Answer:
The other plants did not look as healthy as these plants.

Question 3.
She refused to share her secret. (would not)
Answer:
She would not share her secret.

Question 4.
She went around asking everyone about her plants. (No one / did not)
Answer:
She did not omit anyone when she went around asking about her plants.

7. Make the following Affirmutie using the words given:

Question 1.
There was no breeze. (hardly)
Answer:
There was hardly any breeze.

Question 2.
Their ridicule did not deter her. (failed to)
Answer:
Their ridicule failed to deter her.

Question 3.
Her mother knew nothing about it. (denied)
Answer:
Her mother denied knowing anything about it.

Question 4.
She did not give up. (refuse to)
Answer:
She refused to give up.

8. Imagine that Revathi’s father is abroad on business and she wishes to convey the news of her prize-winning plants. Draft un email for the above subject.
Answer:

Hi Dad,
How are you? How is your trip? Have you done a lot of sightseeing the past weekend? Please don’t forget to send some pics. I wish we could all have been in Paris with you.

I have some excellent news for you. Do you know those potted balsam plants in the corner of our courtyard? Well, I took one pot and gave it a lot of love and care. And guess what! It won the first prize in the ‘Best Plant’ contest in our colony!
But more important than that, Dad, is the fact that I have discovered that my plants love music, especially my favourite raga, Mohanam. They bend towards me when

I play that raga on my violin, and move I away when I play some music with a quick rhythm. No, it is not my imagination; I proved it to the organisers of the contest, and they have praised me for my discovery.I They will certainly talk to you about it when you come back.
Dad, I want to prove my discovery to you too. Please come back soon. Rest everything is fine. Lots of hugs and kisses from all of us.

Revathi.

Class 8 English Chapter 1.4 Revathi’s Musical Plants Additional Important Questions and Answers

Simple Factual Activity:
Fill in the blanks:

Question 1.
The instrument Revathi played was the _____.
Answer:
violin

Question 2.
Revathi’s favourite raga was ______.
Answer:
Mohanam

Question 3.
One day, she saw that there was a pot of ______ plants near the wall.
Answer:
balsam

Question 4.
Revathi decided to participate in the ______ contest to be held in her colony.
Answer:
Best Plant

Question 5.
Use the expression ‘to surmise’ to make a sentence of your own :
Answer:
When the teacher saw Naomi crying, she surmised that she had failed the test.

Pick out the conjunctions in the following sentences:

Question 1.
Her mother said she knew nothing either about the pot or the plants.
Answer:
either…or

Question 2.
The flowers were big and brightly coloured and one of the plants had an unusual kind of flower.
Answer:
and, and.

Complete the table and write who said the given words and to whom:
Answer:

The Words	Who said	To whom
(1) Do plants have ears?	The organisers	Revathi
(2) I know my plants.	Revathi	The organisers

Give reasons:

Question 1.
What shock did Revathi receive on prize distribution day?
Answer:
On prize distribution day, Revathi saw her lost pot of plants on a bench, with the name of a distant neighbour of hers as the competitor. She got a shock when she saw this.

Question 2.
Explain how Revathi planned to convince the organisers that the plants were hers.
Answer:
Revathi knew that her plants were music lovers. She planned to play : the violin and show the organizers how her plants responded to her music and bent their stems towards her. This would convince them that the plants were hers.

Question 3.
The organisers refused to believe that Revathi’s plants were music lovers.
Answer:
The organisers said that plants did not have ears like ours to listen to music. They had never heard of plants enjoying music. Hence, they refused to believe that Revathi’s plants were music lovers.

Punctuate the sentence:

they asked her do plants have ears like ours to enjoy your music
Answer:
They asked her, “Do plants have ears like ours to enjoy your music?”

Underline the nouns in the following sentence :

There was her pot of plants on a bench, with the name of a distant neighbour written on a small piece of cardboard and placed in the soil.
Answer:
There was her pot of plants on a bench, with the name of a distant neighbour written on a small piece of cardboard and placed in the soil.

Personal Response:

Question 1.
What would have been your reaction if you had been in Revathi’s place, and seen someone else’s name on your pot of plants? What would you have done?
Answer:
I would have been furious. I would have gone up to the person whose name was on my plants and shouted at her and tried to make her admit her theft. I would also have complained loudly to the organisers, hoping to shame her into admitting her guilt.

Rewrite the following sentences in the correct order of occurrence in the passage:

1. The organisers were stunned.
2. The neighbour accepted that she had stolen Revathi’s plants.
3. Revathi started playing her favourite raga.
4. Everyone applauded Revathi.

Answer:

1. Revathi started playing her favourite raga.
2. The organisers were stunned.
3. Everyone applauded Revathi.
4. The neighbour accepted that she had stolen Revathi’s plants.

Complex Factual Activities :

Give reasons :

Question 1.
No one suspected that the neighbour had stolen the plants.
Answer:
The neighbour was a regular participant In the competition. Hence, no one suspected that she had stolen the plants.

Question 2.
What is the happy end?
Answer:
In the end, the neighbour admitted j that she had stolen the plants, and that the plants were actually Revathi’s. The plants got the first prize. Everyone applauded Revathi’s discovery. Thus, the end of the story is a happy one.

Activities based on Vocabulary :

Write the noun forms of the following words :

• dejected
• favourite
• applauded
• submitted

Answer:

• dejection
• favour/ favouritism
• applause
• submission

Write the adjective forms of the following words:

• argument
• forgot
• responding
• proudly

Answer:

• argumentative
• forgettable/forgetful
• responsive
• proud

Activities based on Contextual Grammar:

Underline the adverbs in the following sentence:

She felt very dejected but was determined to win her plants back.
Answer:
She felt very dejected but was I determined to win her plants back.

Underline the conjunctions in the following sentence :

The authorities decided that Revathi’s plants deserved the first prize as they were the best-looking and healthy.
Answer:
The authorities decided that Revathi’s plants deserved the first prize as they were the best-looking and healthy.

Personal Response:

What helped Revathi to claim her plants-her belief in magic or her belief in her convictions? Explain your choice.
Answer:
Her belief in her convictions helped Revathi to claim her plants. She was sure that her plants were music lovers and would respond to her favourite raga as they had done before. There was no magic involved. It was a fact.

Grammar

Say whether the following sentences are Assertive, Interrogative, Imperative or Exclamatory:

Question 1.
How happily she played the violin!
Answer:
Exclamatory

Question 2.
They all bent towards her.
Answer:
Assertive

Question 3.
Don’t play that quick tune.
Answer:
Imperative

Question 4.
She kept the knowledge a secret.
Answer:
Assertive

Question 5.
How can plants enjoy music?
Answer:
Interrogative

Question 6.
How proudly did Revathi carry home her prize!
Answer:
Exclamatory

Question 7.
Who could have taken my plants?
Answer:
Interrogative

Question 8.
The organisers were not convinced.
Answer:
Assertive

Do as directed:

Question 1.
Prepare a word register of about 4 words from the lesson for ‘music’.
Answer:
Music – rhythm, tune, violin, raga

Question 2.
Use the phrase ‘pulled up’ in your own sentence :
Answer:
The watchman was pulled up for sleeping when he was on duty.

Question 3.
Spot the error and correct the sentence :That evening, all her friends was going to the prize distribution ceremony.
Answer:
That evening, all her friends were going to the prize distribution ceremony.

Question 4.
Find out four hidden words from the given word : (Each word should have at least 3 letters.) displayed
Answer:
displayed: display, play, plea, leap

Question 5.
Make a pair of sentences to show the difference between two meanings of the following word (homographs) : stem
Answer:
(i) The stem of a plant holds it up to sunlight
(ii) “All your health problems stem from poor eating habits,” said the doctor to Roshan.

Question 6.
Underline the adverbs in the following sentence :
They were slowly moving their stems, bending slightly towards her.
Answer:
They were slowly moving their stems, bending slightly towards her.

Question 7.
Pick out the prepositions in the following sentence :
She had been busy inside the house and had not been to the courtyard.
Answer:
She had been busy inside the house and had not been to the courtyard.

Question 8.
Rewrite using the verb form of the underlined word :
She kept her knowledge a secret.
Answer:
She kept what she knew a secret.

Question 9.
Rewrite using the word ‘normally’ in the sentence:
Plants need light for normal growth.
Answer:
Plants need light to grow normally.

Question 10.
She saw all her plants turn away from her as though they did not like what she was playing.
(Rewrite as an affirmative sentence.)
Answer:
She saw all her plants turn away from her as though they disliked what she was playing.

Balbharti Maharashtra State Board Class 8 English Solutions Chapter 1.3 The Pilgrim Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 8 English Solutions Chapter 1.3 The Pilgrim

Class 8 English Chapter 1.3 The Pilgrim Textbook Questions and Answers

Warming Up:

Make groups and discuss the following using the given points:

Question a.
What fatal dangers/problems did mankind face centuries ago, but are no longer a threat today?
Answer:
(Points : wild animals – lack of food – certain diseases – climate etc.)

Question b.
Name a few scientists/explorers/ social reformers / inventors / discoverers, who spent most of their lives to find solutions to some major problems/ setbacks that mankind faced.
Answer:
(Points : Alexander Fleming, Edison, Ronald Ross, Christopher Columbus, Wright brothers, Raja Ram Mohan Roy, Galileo, Marie Curie, Savitribai Phule, Babasaheb Ambedkar, etc.)

Question c.
Did they themselves suffer from those problems/setbacks?
Answer:
(Points : most did not)

Question d.
What inspired them to spend the best part of their lives to research and share their findings?
Answer:
(Points : a passion for well-being of ! mankind – personal goals and aims – interest in the subject – curiosity – the urge to improve society and help others – etc.)

2. Read and understand the following poetic devices:

(A) If two or more words in the same line convey the some meaning, the Figure of Speech in thut line is called Tautology.
For example: It brought joy and cheer.
They groaned with aches and pains.

(B) ‘Poets often change the proper grammatical order of words in the ¡inc of a poem, in order to make the lines rhyme or to emphasize upon something. The Figure of Speech in such lines is called inersion’ or Anastrophe.’
For example: Up came the sun. Down the hill, it flowed.

(C) When a question is asked in order to create a dramatic effect and not to get an answer, in a line of the poem, the Figure of Speech used is called
Interrogation / Rhetorical Questions:
For example: What is this life, if full of care?
When can their glory fade?

1.Pick out words from the poem to fill in the web diagram. They should be related to the theme in the web.

Answer:

2.The entire poem is metaphorical (Implied comparison).
Match the words in Column A with what they imply in Column B.

Answer:
(1) pilgrim – a dutiful man
(2) journey – life
(3) evening or close of day – old age
(4) chasm, deep and wide – threat to life
(5) building a bridge – solving a problem /getting rid of a threat to life
(6) pitfall – trap
(7) close of day – death

3. A. Read the poem and write 3 qualities of each of the following.

Answer:

3. B. Answer in your own words.

Question a.
Why did the old man have no need to build the bridge, across the chasm?
Answer:
The old pilgrim had already crossed the chasm and would never pass that way again. Hence, the old man had no need to build the bridge across the chasm.

Question b.
What explanation did he give to the fellow- pilgrim for his thoughtful deed?
Answer:
The old man said that though he had already crossed the chasm, there was a fair-haired youth who was about to pass that way. The old man was experienced and was not afraid of the chasm. However, the young man was inexperienced and the chasm could prove to be a pitfall for him.
He too had to cross it at twilight, and the old man was building a bridge to help this youth.

Question c.
What message does the poem convey to all of us?
Answer:
The message that the poem conveys to us is that we must be generous ) and unselfish and think of others. We must try to help others who are not as experienced as we are.

4. A. Note the rhyming words in the first stanza:
way – gray I wide-side- tide / dim -him.
Poet has used a deliberate pattern of lines that rhyme with other lines in the poem or
the stanza. This pattern can be identified by giving the rhyming pairs of words the
same letter of the alphabet.
For example: l stanza of this poem has the pattern AABCCBB
So, AABCCBB is called the Rhyme Scheme of the 1stanza of the poem
‘The Pilgrim’.
Answer:
(i) the 2nd stanza : ddaabb
(ii) the 3rd stanza: eeaaffcc

4. B. Now write the Rhyme Scheme of the 2stanza and 3 stanza
Remember that a line in the 2d or stanza may rhyme with lines in P’ stanza,
too. You may use the sanie letter of the alphabet as used in the 1 stanza.
Answer:
(i) Came at evening, cold and gray. To a chasm, deep and vast and wide.
(The correct prose order Is: Came on a cold and gray evening to a deep and wide and vast chasm.)
(ii) To the fair-haired youth. may a pitfall be.
(The correct prose order is : To the fair-haired youth, It may be a pitfall.)

4. C. Find two lines from the poem that j contain the figure of speech ‘Inversion’.
Answer:
(i) Came at evening, cold and gray, To a chasm, deep and vast and wide.
(The correct prose order is : Came on j a cold and gray evening to a deep and wide and vast chasm.)
(ii) To the fair-haired youth, may a pitfall be.
(The correct prose order is : To the fair-haired youth, it may be a pitfall.)

Pick out one line each that contains the following figures of speech:
(Note: Refer to the next page for the explanation.)

Question a.
Tautology:
Answer:
To a chasm, deep and vast and wide.
The words vast and wide have similar meaning.

Question b.
Personification:
Answer:
A pilgrim, going a lone highway.
The highway is given the human quality of being lonely.

Question c.
Interrogation:
Answer:
Why waste your time in building here?
A question is asked to emphasize an idea.

5. Imagine that you are the fellow – pilgrim and you wish to share your experience of the incident in the poem. Write a short article about it for a magazine / journal. Also convey what change it has brought in our life.

Class 8 English Chapter 1.3 The Pilgrim Additional Important Questions and Answers

Complete the following:

Question 1.
Although he had already crossed the chasm, the pilgrim ________.
Answer:
paused and built a bridge across the waters.

Question 2.
The old pilgrim built the bridge to to __________.
Answer:
help the Inexperienced youth who was following on the same path.

Complex Factual Activities:
Give reasons:

Question a.
The fellow pilgrim was puzzled.
Answer:
The old pilgrim had already crossed the chasm and would never pass that way again. Yet, he was building a bridge across the chasm. The fellow pilgrim could not understand the reason for this and was hence puzzled.

Question b.
What/Who could be the third pilgrim?
Answer:
The third pilgrim could be a young, inexperienced youth.

Analysis/Appreciation Of A Poem
Answer:
(1) Poem and poet: ‘The Pilgrim’ by Will Allan Dromgoole
(2) Theme: Those who have faced the difficulties of life successfully and are experienced must be unselfish and help those who are inexperienced and may face difficulties.
(3) Tone: Serious.
(4) Structure and stanzas: Stanzas of unequal length; 1st stanza – 7 lines; 2nd stanza – 6 lines; 3rd stanza – 8 lines;
(5) Rhyme and Rhythm: 1st stanza – AABCCBB; 2nd stanza – ddaabb; 3rd stanza – eeaaffcc
(6) Language and Imagery: The narrative is direct with some archaic language used; there is a strong underlying message. The descriptions are vivid.
(7) Figures of Speech: Inversion, Tautology, Personification, Interrogation.

Writing Skills:

“Imagine that you are the fellow-pilgrim and you wish to share your experience of \ the incident in the poem. Write a short j article about it for a magazine/journal.
Also convey what change it has brought in your life.
Answer:

The Turning Point

There are certain incidents in one’s life which have an impact on a person and prove to be a turning point in their lives. Let me narrate the incident which shook me awake.

I was on a hike in some hilly places when I had to cross a deep ravine which had a gushing river flowing through it. I managed to cross without any difficulty to my surprise, an old man ahead of me also crossed it nimbly. As I was about to continue on my way, I saw the old man turn back and build a rough bridge across the water. It took a lot of effort and I stood by wondering. Finally, I asked him, “Sir, it is late evening and you Eire not likely to cross this way again. Why are you building a bridge now?”

The old man’s answer floored me. “You confused child,” he said with a smile. “I have completed my journey – true. But behind me is a young boy who is inexperienced.

He will soon reach this chasm, and he may have difficulty in crossing it. I am building this bridge to help him.”
I stood still, amazed at the generosity and unselfishness of the old man, who was putting in the time and effort to help someone he did not even know. He was building a bridge that he would never ever cross.

This incident left an indelible mark on my mind. Since that time, I always try to help others even though it may not be beneficial to me in any way. However, it gives me something immeasurable – peace and happiness. Try it out, won’t you? (indelible – permanent; unfading)

Balbharti Maharashtra State Board Class 8 English Solutions Chapter 1.1 A Time To Believe Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 8 English Solutions Chapter 1.1 A Time To Believe

Class 8 English Chapter 1.1 A Time To Believe Textbook Questions and Answers

Warming Up:

Question 1.
Think, choose and fill up the labels with what a ‘sunrise’ symbolizes.
(jewellery / art / hope / birth / anger / new opportunities / good manners / inspiration/ new achievements / happiness / misery / bright moments / new aims / money / newsurprises)

Answer:

Question 2.
An acrostic is a poem or a write up in which the first letter of each line forms a word, when it is read vertically. Complete the acrostics of BELIEVE and FAITH.

With your benchmate / group, complete the acrostic of BELIEVE and FAITH.
Answer:

1.A. Rearrange the letters to make meaningful words, occurring in the poem.

1. clearmis
2. sowmid
3. tabyue
4. madres
5. laveu
6. downre

Answer:

1. miracles
2. wisdom
3. beauty
4. dreams
5. value
6. wonder

1.B. Write words from the poem that describe the following.

1. sky
2. heart
3. hand
4. beginning

Answer:

1. stardust sky
2. nurturing heart
3. aging hand
4. new beginning

2. Say WHY. . . . .

Question a.
________ the sky has a magical quality.
Answer:
The sky has a magical quality because it has scurrying clouds, twinkling stars and a beautiful moon.

Question b.
_______ even an aging hand has beauty.
Answer:
because it can teach us how to love.

Question c.
_______we should believe that we are strong and courageous.
Answer:
We should believe that we are | strong and courageous so that we can recover after we have gone through difficulties and shocks, and return to our normal lives again.

3. Make a list of any six things that the poet wants us to accept as true.
Answer:
The poet wants us to accept as j true the following things :

• that we have the strength and ( courage to get back to normal after a setback
• that we are never alone
• that life is a gift we must cherish
• that there are wonderful surprises in store for us
• that all our hopes and dreams are within reach
• that great things will happen if we have belief in life and in ourselves

4. Find from the poem, positive qualities to fill up the web.

Answer:

5. Read the lines below.
(A) ‘To believe is to see angels dancing among the clouds’.
The above line contain a human characteristic ‘dancing’ given to something
non – human, ‘angels’. The Figure of Speech used in the line is called
‘Personification’.

(B) ‘To believe is to know that
Everyday is a new beginning’.

(C) To believe is to know ………. life is a gift
Lines in poetry, such as the above, state a general truth and can be used as sayings or
quotes etc. They contain the Figure of Speech called Epigram.
Epigram closely resembles a proverb.

Find from the poem three other examples of Epigram.
Answer:
(i) ‘To believe is to find the strength and courage that lies within us.’
(ii) ‘To believe is to know we are never alone, that life is a gift.’
(iii) ‘To believe is to know that wonderful surprises are just waiting to happen.’
(These lines state a general truth.)

6. Divide the class into 5 groups. Each group can prepare a decorative chart / poster using an epigrammatic lines from the poem. You may use calligraphy / painting / or Paint programme on a computer. (With permission, put up these charts in your school.)

Class 8 English Chapter 1.1 A Time To Believe Additional Important Questions and Answers

Complete the following:

Question 1.
One should know and trust _______.
Answer:
One should know and trust that every day is a new beginning, that miracles happen and dreams really do come true.

Question 2.
The two supernatural references in the second stanza _______.
Answer:
The two supernatural references in the second stanza are to angels and to the man in the moon.

Activities based on Poetic Devices/Vocabulary:

Question 1.
Find out an example of Personification from the extract.
Answer:
‘To believe is to see angels dancing among the clouds.’ (Here, the angels have been given the human quality of ‘dancing’.)

Question 2.
Pick out examples of Alliteration from the extract.
Answer:
(i) …. and the wisdom of the man in the moon’. (Repetition of the sound of the letter ‘m’.)
(ii) For it is through their teachings, we learn to love. (Repetition of the sound of the letters ‘t’ and T.)

Question 3.
Pick out an example of Repetition from the extract.
Answer:
The words ‘To believe is to ….’ are repeated at the beginning of each stanza. This provides emphasis to the message in the poem and gives rhythm to the stanzas.

Complete the following:

Question 1.
The two qualities that are needed to recover after a shocking event are _________.
Answer:
strength and courage.

Question 2.
The poet advises everybody to ______.
Answer:
have a positive attitude.

Complex Factual Activities:

Question 1.
Explain why ….
…. we should believe that we are strong and courageous,
Answer:
We should believe that we are strong and courageous so that we can recover after we have gone through difficulties and shocks, and return to our normal lives again.

Activities based on Poetic Devices/Vocabulary :

Question 1.
Rearrange the letters to form meaningful words occurring in the extract.

1. gearuoc
2. rissupser
3. gnehtrts
4. irehchs

Answer:

1. courage
2. surprises
3. strength
4. cherish

Question 2.
Write word from the extract that describe the following :
surprises
Answer:
wonderful surprises

Question 3.
Pick out an example of Metaphor from the extract.
Answer:
‘That life is a gift.’ Life is implicitly compared to a gift.

Question 4.
Pick out an example of Repetition from the extract.
Answer:
The words ‘To believe is to ….’ are repeated at the beginning of each stanza. This provides emphasis to the message in the poem and gives rhythm to the stanzas.

Question 5.
Analysis/Appreciation Of The Poem ‘A Time To Believe’
Answer:
Poem and poet: ‘A Time to Believe’ by B.J. Morbitzer.
Theme: To believe in ourselves and to have a positive and optimistic attitude towards life.
Tone: Serious and inspirational.
Structure and stanzas: 4 lines in each stanza, except in the last stanza, which has 5 lines.
Rhyme and Rhythm: No rhyme scheme; the poem is written in free verse.
Language and Imagery: The language is simple and direct. The only instances of Imagery are of ‘angels dancing among the clouds’ and the ‘stardust sky’.
Figures of Speech: Personification, Epigram, Repetition, Metaphor.

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 12 Introduction to Acid and Base Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 8 Science Solutions Chapter 12 Introduction to Acid and Base

Class 8 Science Chapter 12 Introduction to Acid and Base Textbook Questions and Answers

1. Identify the following solutions, whether they are acid or base.

Question a.

Answer:

2. Write chemical names from given formulae.
H₂SO₄, Ca(OH)₂, HCl, NaOH, KOH, NH₄OH

Question a.
Write the chemical names from given formulae: H₂SO₄, Ca(OH)₂, HCl, NaOH, KOH, NH₄OH
Answer:

1. H₂SO₄ – Sulphuric acid
2. Ca(OH)₂ – Calcium hydroxide
3. HCl – Hydrochloric acid
4. NaOH – Sodium hydroxide
5. KOH – Potassium hydroxide
6. NH₄OH – Ammonium hydroxide

3. Sulphuric acid has highest importance in chemical Industry. Why?

Question a.
Sulphuric acid has highest importance in chemical Industry. Why?
Answer:
Answer:
Sulphuric acid has highest importance in the chemical industry because it is used in the manufacturing of fertilizers like ammonium sulphate and superphosphate of lime. It is used in the manufacturing of hydrochloric acid, nitric acid, phosphoric acid, ether, plastics and metal sulphates. It is also used in the manufacturing of dyes, drugs, perfumes, disinfectants and glue.

4. Give answers.

Question a.
Which acid is used for getting chloride salt?
Answer:
Hydrochloric acid is used for getting chloride salt.

Question b.
By squeezzing lemon on a piece of rock the gas liberated turned lime water milky. Which compound is present in the rock?
Answer:
Metal carbonate is present in the rock.

Question c.
The label on the bottle of chemical is spoiled. How will you find whether the chemical is acidic or not?
Answer:
The chemical is tested with blue litmus paper. If it turns red it is an acidic otherwise tested with red litmus paper, if it turns blue, it is an alkaline.

5. Answer the following questions. 

Question a.
Explain the difference between acid and base.
Answer:
Acids:

1. Acids have sour taste.
2. Acids turn blue litmus red.

Bases:

1. Bases have bitter taste.
2. Bases turn red litmus blue.

Question b.
Why indicator does not affect by salt?
Answer:
Mostly indicators are organic compounds which do not react with a salt.

Question c.
Which substances are produced i by neutralization process?
Answer:
Salt and water are produced in the f neutralization process.

Question d.
Which are the industrial uses of acids?
Answer:
Acids which are used in the industry are:

1. Sulphuric acid
2. Hydrochloric acid
3. Nitric acid.;

1. Sulphuric acid: Sulphuric acid is 5 used (a) in the manufacture of chemical? fertilizers like ammonium sulphate, (b) for cleaning gold and silver articles and (c) in car batteries.

2. Hydrochloric acid: Hydrochloric acid is used (a) to clean toilets and (b) to obtain glucose from starch and also for producing gelatine.

3. Nitric acid: Nitric acid is used (a) in the manufacture of perfumes (b) for engraving on copper, brass or silver and (c) in the manufacture of paints and explosives.

6. Select proper word given in bracket and fill in the blanks.

Question a.
Main constituent of acid is ……………. .
Answer:
Main constituent of acid is H⁺ ion.

Question b.
Main constituent of alkali is …………….. .
Answer:
Main constituent of alkali is OH^– ion.

Question c.
Tartaric acid is a …………… acid.
Answer:
Tartaric acid is a weak acid.

7. Match the pairs. 

Question a.

Group A	Group B
1. Tamarind	a. Acetic acid
2. Curd	b. Citric acid
3. Lemon	c. Tartaric acid
4. Vinegar	d. Lactic acid

Answer:

Group A	Group B
1. Tamarind	c. Tartaric acid
2. Curd	d. Lactic acid
3. Lemon	b. Citric acid
4. Vinegar	a. Acetic acid

8. State true or false.

Question a.
Oxides of metals are alkaline in nature.
Answer:
True.

Question b.
Salt is acidic.
Answer:
False. (Salt is neutral)

Question c.
Metal corrodes due to salts.
Answer:
False. (Acids and bases corrode metals)

Question d.
Salts are neutral.
Answer:
True. (Not all salts neutral)

9. Classify the following substances into acidic, basic and neutral group:
HCl, NaCl, MgO, KCl, CaO, H₂SO₄, HNO₃, H₂O and Na₂CO₃.

Question a.
Classify the following substances into acidic, basic and neutral group:
HCl, NaCl, MgO, KCl, CaO, H₂SO₄, HNO₃, H₂O and Na₂CO₃.
Answer:

Group	Substances
Acid	HCl, H2SO4, HNO3
Base	CaO, MgO, Na2CO3
Neutral	H2O, NaCl, KCl.

Project:

Question a.
Write in your own language the uses and importance of neutralization reaction in daily life.

Class 8 Science Chapter 12 Introduction to Acid and Base Important Questions and Answers

Fill in the blanks:

Question 1.
Acid reacts with metal to form …………. gas.
Answer:
Acid reacts with metal to form hydrogen gas.

Question 2.
DNA is an acid present in our body, it decides …………. properties.
Answer:
DNA is an acid present in our body, it decides heredity properties.

Question 3.
The chemical formula of milk of magnesia is ………….
Answer:
The chemical formula of milk of magnesia is Mg (OH)₂.

Question 4.
…………. are used to control hyperacidity.
Answer:
Antacids are used to control hyperacidity.

Question 5.
Alkali has …………. taste.
Answer:
Alkali has bitter taste.

Question 6.
Proteins are made up of ………….
Answer:
Proteins are made up of amino acids.

Question 7.
…………. is used in batteries.
Answer:
Dil. H₂SO₄ is used in batteries.

Rewrite the following statements by selecting the correct options:

Question 1.
The colour of phenolphthalein indicator in alkaline solution is ………….
(a) yellow
(b) green
(c) orange
(d) pink
Answer:
The colour of phenolphthalein indicator in alkaline solution is pink.

Question 2.
…………. is sour to taste.
(a) An acid
(b) An alkali
(c) A salt
(d) Alcohol
Answer:
An acid is sour to taste.

Question 3.
When phenolphthalein is added to NaOH, the colour of the solution will become ……………… .
(a) colourless
(b) red
(c) pink
(d) yellow
Answer:
When phenolphthalein is added to 5 NaOH, the colour of the solution will become pink.

Question 4.
When phenolphthalein is added to HCl, the colour of the solution will be ………….. .
(a) red
(b) pink
(c) green
(d) colourless
Answer:
When phenolphthalein is added to HCl, the colour of the solution will be colourless.

Question 5.
…………. is a natural indicator.
(a) Phenolphthalein
(b) Methyl orange
(c) Litmus
(d) Methyl red
Answer:
Litmus is a natural indicator.

Question 6.
The litmus paper or the litmus solution is obtained from …………. plants.
(a) moss
(b) rose
(c) hibiscus
(d) lichen
Answer:
The litmus paper or the litmus solution is obtained from lichen plants.

Question 7.
…………. is not an alkali.
(a) Sodium hydroxide
(b) Potassium hydroxide
(c) Copper hydroxide
(d) Calcium hydroxide
Answer:
Copper hydroxide is not an alkali.

Question 8.
…………. is a weak acid.
(a) Hydrochloric acid
(b) Nitric acid
(c) Carbonic acid
(d) Sulphuric acid
Answer:
Carbonic acid is a weak acid.

Question 9.
When methyl orange is added to HCl, the colour of the solution will be …………… .
(a) red
(b) pink
(c) yellow
(d) colourless
Answer:
When methyl orange is added to HCl, the colour of the solution will be pink.

Question 10.
When blue litmus paper is added to NaOH, the colour of the litmus paper will be ……………. .
(a) blue
(b) red
(c) pink
(d) yellow
Answer:
When blue litmus paper is added to NaOH, the colour of the litmus paper will be blue.

State whether the following statements are true or false. If a statement is false, correct it and rewrite:

Question 1.
Red cabbage is a natural indicator.
Answer:
True

Question 2.
Fats of our body are formed by fatty acids.
Answer:
True.

Question 3.
Ammonium hydroxide is used in the production of fertilizers.
Answer:
True.

Question 4.
Lime water is a weak acid.
Answer:
False. (Limewater is a weak base)

Question 5.
Orange colour of methyl orange turns yellow in acid.
Answer:
False. (Orange colour of methyl orange turns pink in acid)

Question 6.
Methyl red turns yellow in alkali.
Answer:
True.

Question 7.
Oxalic acid is used in aerated cold drinks.
Answer:
False. (Carbonic acid is used in aerated cold drinks).

Find the odd one out and justify:

Question 1.
Acetic acid, carbonic acid, hydrochloric acid, nitric acid.
Answer:
Acetic acid. (Others are mineral acids.)

Question 2.
Hydrogen chloride, sodium hydroxide, calcium oxide, ammonia.
Answer:
Hydrogen chloride. (Others are bases.)

Question 3.
HCl, CH₃COOH, H₂SO₄, HNO₃
Answer:
CH₃COOH. (Others are strong acids.)

Question 4.
NaOH, Ca(OH)₂, NH₄OH, Ba(OH)₂
Answer:
NaOH (Others are weak bases.)

Question 5.
H₂SO₄, H₂CO₃, HCl, HNO₃
Answer:
H₂CO₃ (Others are strong acids.)

Question 6.
Citric acid, formic acid, lactic acid, nitric acid.
Answer:
Nitric acid. (Others are organic acids.)

Question 7.
Lime, litmus, phenolphthalein, methyl orange.
Answer:
Lime. (Others are indicators.)

Match the following:

Question 1.

Column ‘A’	Column ‘B’
1. Strong acid	a. Magnesium hydroxide
2. Weak alkali	b. Carbonic acid
3. Weak acid	c. NaOH
4. Strong alkali	d. Nitric acid

Answer:

Column ‘A’	Column ‘B’
1. Strong acid	d. Nitric acid
2. Weak alkali	a. Magnesium hydroxide
3. Weak acid	b. Carbonic acid
4. Strong alkali	c. NaOH

Question 2.

Column ‘A’	Column ‘B’
1. Sodium hydroxide	a. Whitewashing
2. Magnesium hydroxide	b. Fertilizers
3. Calcium hydroxide	c. Washing soap
4. Ammonium hydroxide	d. Antacid

Answer:

Column ‘A’	Column ‘B’
1. Sodium hydroxide	c. Washing soap
2. Magnesium hydroxide	d. Antacid
3. Calcium hydroxide	a. Whitewashing
4. Ammonium hydroxide	b. Fertilizers

Define the following:

1. Acid: A substance which gives H⁺ ions in water is called an acid.

2. Alkali: A substance which gives OH^– ions in water is called an alkali.

3. Indicator: Substances which change their colours in presence of acid or base are called indicators.

4. Neutralization: The reaction between an acid and an alkali to form the r salt and water is termed as neutralization.

Answer the following questions in one sentence each:

Question 1.
What are natural acids?
Answer:
Acids present in foodstuffs are called natural acids.

Question 2.
State three vegetables from which natural indicators can be prepared.
Answer:
Natural indicators: Red cabbage, radish, tomato.

Question 3.
State names of any three strong acids.
Answer:

1. Hydrochloric acid
2. Sulphuric acid
3. Nitric acid.

Question 4.
State the names of the acids found in lemon juice, Amla, tamarind water and curd.
Answer:

1. Lemonuice – citric acid
2. Amla – ascorbic acid
3. tamarind water – tartaric acid
4. curd – lactic acid.

Question 5.
State names of any three alkalis.
Answer:

1. sodium hydroxide
2. potassium hydroxide
3. calcium hydroxide.

Question 6.
State the names of three indicators.
Answer:

1. Litmus paper
2. Methyl orange
3. Phenolphthalein.

Question 7.
State the names of three weak alkalis.
Answer:

1. Calcium hydroxide
2. ammonium hydroxide
3. magnesium hydroxide.

Question 8.
From which plant is litmus obtained?
Answer:
Litmus is obtained from plants called lichens.

Question 9.
Name the antacid which is used to control the hyper acidity.
Answer:
Milk of magnesia [Mg(OH)₂] is used to control the hyper acidity.

Question 10.
How will you neutralize the excess of acid present in the soil?
Answer:
Lime stone or lime water is mixed in the soil to neutralize the excess of acid.

Question 11.
When lemonuice falls on a marble kitchen counter, which is the gas that bubbled out?
Answer:
Carbon dioxide.

Answer the following questions:

Question 1.
What are indicators?
Answer:
Substances which change their colours in presence of acid or base are called indicators.

Question 2.
State two acid-base indicators and mention their colour change.
Answer:
Phenolphthalein and methyl orange are two acid-base indicators. Phenolphthalein is colourless in an acidic solution while it turns pink in a basic solution. Methyl orange gives orange colour with an acidic solution and yellow colour with a basic solution.

Question 3.
State the colour change for each of the following solutions with red litmus, blue litmus, phenolphthalein and methyl orange solutions.
Answer:

Question 4.
Name the acid present in (1) Orange (2) Vinegar (3) Tamarind (4) Curd (5) Tomato (6) Lemon.
Answer:

Substance	Acid
Orange	Citric acid
Vinegar	Acetic acid
Tamarind	Tartaric acid
Curd	Lactic acid
Tomato	Oxalic acid
Lemon	Citric acid

Question 5.
Classify the following into acidic substances, basic substances and salts.
(1) Lime water, (2) soda water, (3) soap water, (4) sea water, (5) sweet limeuice, (6) sugar caneuice, (7) buttermilk, (8) a mixture of ash in water, (9) tamarind water.
Answer:
a. Acidic substances: (1) Soda water, (2) sweet limeuice, (3) buttermilk, (4) tamarind water.
b. Basic substances: (1) Lime water, (2) Soap water, (3) a mixture of ash in water.
c. Salts: (1) Sea water, (2) sugar caneuice.

Question 6.
What happens when sour substances like limeuice, tamarind water falls on shahabad stones or kitchen platform? Why?
Answer:
When sour substances like limeuice, tamarind water falls on shahabad stones or kitchen platform, citric acid present in limeuice and tartaric acid in tamarind water reacts with metal carbonates present in shahabad stones or kitchen platform, carbon dioxide gas is evolved resulting in the formation of uneven surface.

Question 7.
Collect soil samples from your surroundings and find out whether it is acidic or alkaline or neutral?
Answer:
Soil samples collected from the surroundings are acidic in nature.

Question 8.
Which substances are used to clean greenish stains on copper vessels and to shine blackish silver utensils?
Answer:
Tamarind pulp is used to clean greenish stains on copper vessels. To shine blackish silver utensils, ammoniacal solution or limeuice or detergent is used.

Question 9.
Why toothpaste is used for brushing teeth?
Answer:

1. Toothpaste contains fluorides and alkali to neutralize the mouth acid.
2. Hence, the tooth paste, which is generally alkaline, is used for cleaning the teeth as it can neutralize the excess acid in i the mouth and prevent tooth decay.

Question 10.
State the properties of acids.
Answer:

1. Acids are sour in taste.
2. Acid molecules contain hydrogen ion (H⁺) as a main constituent.
3. Acid reacts with metal to form hydrogen gas.
4. Acid reacts with carbonates and liberates CO₂ gas.
5. Blue litmus turns red in acid.

Question 11.
State the uses of acids.
Answer:

1. Acids are used in the production s of chemical fertilizers.
2. Acids are used in the production of explosives, oil purification, medicines, dyes and paints.
3. Hydrochloric acid is used for the preparation of different types of chloride salts.
4. Dil. H₂SO₄ acid is used in the batteries (electric cell).
5. Dil. HCl is used for sterilization of water.
6. Acid is used for making of white paper from wood pulp.

Question 12.
The iron knife shines better after cutting the sour fruits like lemon, raw mangoes. Why?
Answer:
Acids present in sour fruits clean and dissolves the salts present on the surface of iron knife as a result iron knife shines better after cutting the sour fruits.

Question 13.
What is meant by neutralization? Give example.
Answer:
When an acid reacts with an alkali to form a salt and water, it is called neutralization.

Give scientific reasons:

Question 1.
When we have stomachache, doctors prescribe medicine containing magnesium hydroxide.
Answer:

1. There is hydrochloric acid in our stomach which helps in the digestion of food.
2. Sometimes in the stomach, there is more hydrochloric acid than we need.
3. This excess acid causes acidity and indigestion resulting in stomachache.
4. When magnesium hydroxide is administered it neutralizes the extra acid in the stomach.
5. Therefore, magnesium hydroxide is the best cure for stomachache.
6. So, when we have stomachache, doctors prescribe medicine containing magnesium hydroxide.

Question 2.
Quicklime or slaked lime is added to the soil.
Answer:

1. When chemical fertilizers are added to the soil, the soil becomes acidic.
2. To reduce its acidity quicklime or slaked lime is added to the soil.

Question 3.
Tarnished and stained copper vessels are brought to a shine by using tamarind pulp.
Answer:
In due course, unus6d copper vessels
are covered with a coating of black copper oxide and other compounds of copper which tarnish the vessel. Tamarind contains tartaric acid. When the vessel is rubbed with tamarind pulp, tartaric acid reacts with copper oxide and removes the layer. Thus, the copper vessel regains its shine.

Question 4.
Copper and brass utensils are tinned.
Answer:
Copper and brass reacts with i organic acids present in food materials and poisonous salts are formed. Tin does not react with organic acids present in food materials. Therefore, copper or brass vessels are tinned.

Distinguish between acid and alkali. OR Distinguish between the following:

Question 1.
Acid and Alkali:
Answer:

Acid	Alkali
1. Acid has sour taste.	1. Alkali has bitter taste.
2. Acid turns blue litmus red.	2. Alkali turns red litmus blue.
3. An acid in an aqueous solution gives H+ ions.	3. An alkali in an aqueous solution gives OH+ ions.
4. Oxides of non – metals form acids.	4. Oxides of metals form bases.

Activity-based questions:

Activity 1:
Apparatus: Hibiscus, rose, turmeric, red cabbage leaves, filter paper, etc.
Activity: Rub red petals of hibiscus flower on the white filter paper. This gives hibiscus indicator paper. Similarly rub, rose petals on the white filter paper. Cut strips of this paper, it is a rose indicator paper. Take turmeric powder, add a little water in it. Dip filter paper or ordinary paper in the turmeric water for some time.

After drying make strips of that paper. Prepare turmeric indicator paper in this way. Put leaves of red cabbage in small quantity of water and heat it. Once solution of cabbage leaves cool down, dip papers in it and dry it. Make strips of dried paper. In this way prepare red cabbage indicator paper. Put some drops of following substances on the indicator papers prepared by the above method and write the effect in the following table:

Substance	Effect on turmeric paper	Acidic/basic
1. Lime juice	Yellow	Acidic
2. Lime water (calcium hydroxide)	Red	Basic
3.

Activity 2:
Take baking powder. Add a little water to it. Add this solution on to limeuice, vinegar, orangeuice, appleuice, etc. and note the findings.
What do you observe on addition of baking soda solution in the fruituice? Whether bubbles formed or effervescence came out of fruituice?
From the above first activity we came to know that yellow turmeric indicator paper’s turns red in certain solutions. Similarly on addition of baking soda solution in the acidic solution bubbles come out or effervescence is produced.
By these simple and easy activity we can identify acidic or alkaline substance:
[Note for Activity 1 and Activity 2: Students should perform the experiments under the guidance of school teachers and record their observations.]

Activity 3:
Under the guidance of teacher take limeuice, ammonium hydroxide (NH₄OH), dil. hydrochloric acid (dil. HCl) and nitric acid (HNOs) in different test-tubes. Add drops of following indicators in them. Also dip litmus papers in the solutions. Observe and record in the following table.

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 18 Ecosystems Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 8 Science Solutions Chapter 18 Ecosystems

Class 8 Science Chapter 18 Ecosystems Textbook Questions and Answers

1. Complete the following by using the correct option:

Question a.
Air, water, minerals, soil are ………….. factors of an ecosystem. (physical, organic, inorganic)
Answer:
Air, water, minerals, soil are physical factors of an ecosystem.

Question b.
River, ponds, ocean are …………. ecosystems, (land, aquatic, synthetic)
Answer:
River, ponds, ocean are aquatic ecosystems.

Question c.
Man is ………….. in an ecosystem. (producer, consumer, decomposer)
Answer:
Man is consumer in an ecosystem.

2. Match the following:

Question a.

Producer	Ecosystem
1. Cactus	a. Forest
2. Aquatic plants	b. Creek
3. Mangroves	c. Aquatic
4. Pine	d. Desert

Answer:

Producer	Ecosystem
1. Cactus	d. Desert
2. Aquatic plants	c. Aquatic
3. Mangroves	b. Creek
4. Pine	a. Forest

3. Give my information:

Question a.
Ecosystem.
Answer:
Ecosystem is the structure formed by the interrelationships between the living organisms and non-living components in their surrounding habitats. Living organisms are also called biotic factors while the non-living components are called abiotic factors. The abiotic and biotic factors have a reciprocal relationship with each other. The ecosystem has plants as producers, animals as consumers and microbes as decomposers.

The decomposers return the substances back to the nature by process of decomposition in which the organic complex molecules are reduced to their inorganic constituents. Thus the dead remains of plants and animals are once again recycled back to the nature in any healthy ecosystem.

Question b.
Biome.
Answer:
Biomes are a larger collection of small ecosystems which are similar in their structure. In a particular biome there are same climatic, abiotic factors and similar living organisms. Biomes are of two main types, land biomes and aquatic biomes. The land biomes exist only on land. Land biomes are of following subtypes based on the abiotic factors. E.g. Grasslands, evergreen forests, deserts, Tundra ecosystem, ecosystems in Taiga, tropical rainforests, etc. Aquatic biomes include freshwater ecosystem, marine ecosystem and brackish water ecosystem found in the creeks.

Question c.
Food web.
Answer:
The complex feeding relationships form a food web. In nature in any ecosystem, the food chains are not straight and linear. But these are quite complex. A prey is consumed by a predator but this predator can itself be a prey to some other predator. E.g. Frog is a predator for variety of insects but frog is preyed upon by snake and the snake can be eaten by a bird. The same bird can also feed on insects or frog. The interrelationships between different biotic components of any ecosystem thus form the complicated food web.

4. Give scientific reasons: 

Question a.
Plants in an ecosystem are called producers.
Answer:
are cut down causing deforestation. The wild animals lose their habitat. Many of them become extinct. There is great loss of flora and fauna due to construction of large dams. There is undue pressure on the land surface caused due to stored water column. This may cause earthquakes. The human settlements are removed as their houses and farms are immersed under water. In all the above ways large dams destroy the ecosystems.

Question b.
Large dams destroy ecosystems.
Answer:
When a large dam is constructed, the original landscape is changed. The trees are cut down causing deforestation. The wild animals lose their habitat. Many of them become extinct. There is great loss of flora and fauna due to construction of large dams. There is undue pressure on the land surface caused due to stored water column. This may cause earthquakes. The human settlements are removed as their houses and farms are immersed under water. In all the above ways large dams destroy the ecosystems.

Question c.
Rhinos were restored in Dudhwa forest.
Answer:
Long ago in last century, Dudhwa forest was the natural habitat of the one-horned Rhino. However, due to hunting and poaching, the Rhino became almost extinct. In order to restore it back the breeding in captivity was attempted and the young ones were released in the natural habitat. Saving the precious wildlife is important and hence these efforts were done.

5. Answer the following:

Question a.
What are the effects of increased population (of human beings) on ecosystems?
Answer:

1. Human population growth rate is very big as compared to other animals.
2. Moreover, they are apex consumers in an ecosystem. Just like any other organisms, ecosystems provide all the basic needs to humans, too.
3. However, man demands much more due to excessive population. The natural resources are utilized on the large scale only by man.
4. Changing lifestyles, consumerism, degradation of nature and pollution are certain aspects which are created only by human beings.
5. All these cause increased stress on the ecosystems. Large human population also produces large-scale solid wastes.

Question b.
How is urbanization responsible for destruction of ecosystems?
Answer:
When people do not get sufficient food and other amenities, they migrate to the cities. The cities provide employment for many people due to industries, factories and other facilities. Every day many people migrate to cities. This causes urbanization. Due to increased population in cities, there is more need for housing. This results in loss of agricultural lands, marshlands, wetlands, forests and grasslands, etc.

The natural ecosystems are lost in an attempt to have developmental work. Human interference causes changes in the ecosystems. When land usage is changed many naturally occurring species of plants and animals are exterminated. Animal- human conflicts are very common in newly established urban areas which are near the natural forests.

Question c.
What are the reasons for war?
Answer:
There are difference of opinions and competition over land, water, mineral resources, etc. among neighbouring countries. Moreover, there can be economic and political causes which lead to war among different countries. Many times the l religions and ethnicity are also caused for dispute. Due to international conflicts, the peace is disturbed and it results in war.

Question d.
Explain the interactions among the factors of an ecosystem.
Answer:

1. The abiotic factors such as air, water, soil, sunlight, temperature, humidity, etc. affect the biotic factors, i.e. the surviving plants, animals and microbes in the ecosystem.
2. The type of abiotic factors in an ecosystem determine the survival of biotic factors. The population of these biotic factors is also dependent on the quality of abiotic factors.
3. The proportion of abiotic factors in an ecosystem fluctuates as biotic factors use up or release particular abiotic factors.
4. Every biotic factor also interacts with its necessary abiotic factors as well as other biotic factors around it.

Question e.
Differentiate between evergreen forests and grasslands.
Answer:

Evergreen forests	Grasslands
1. About seven percent of the Earth’s surface is occupied by evergreen forests.	1. About 30 percent of the Earth’s surface is covered by grasslands.
2.  More than half of the earth’s terrestrial plants and animals are seen in evergreen forests.	2. Grazing animals are seen in grasslands.
3. Tropical evergreen forests are dense, multi-layered.	3. Grasslands consist of tall grass. There are wild grasses and there may be some trees.
4. These forests are found in the areas receiving more than 200 cm annual rainfall i.e. very heavy rainfall.	4. There is an average of 20 – 35 inches of rainfall a year in grasslands.
5. Tropical regions show evergreen forests.	5. Several parts of the world have grasslands.

6. Describe the following pictures:

Question a.
Describe the following pictures

Answer:
The picture no. 1 is showing desert ecosystem, while the picture no. 2 is showing a forest ecosystem where a wetland (a lake) is also shown. In desert ecosystem, the producers are green cactus and a palm tree. Since in desert there are scanty rains, the vegetation is very less. The soil is sandy soil. The consumers of the desert are also limited.

In the above picture camel is shown which is a primary consumer in the desert ecosystem. Camel is very well adapted for desert life. There is also the scarcity of water in desert and hence cactus shows xerophytic (suitable to survive in desert) adaptations.

In second picture, the forest ecosystem is shown because we can see elephant and tiger in the picture. Also, giant hornbill is sitting on the tree. This forest must be tropical evergreen forest. The rainfall is heavy in such areas and hence different types of wetlands can be seen in forests. Wetlands support variety of life. A separate aquatic ecosystem does exist here which is closely interconnected with the terrestrial ecosystems through food chains and food web.

The birds utilize the fish as their prey. The wild animals come to wetlands to quench their thirst. In this picture the plants, grass, etc. are producers, small fishes in the lake are primary consumers. They will be eaten by larger fishes which are secondary consumer in the aquatic ecosystem. The elephant is herbivorous animal and hence it is primary consumer. Snake is the secondary consumer while the birds of prey (eagle that is flying) and tiger are tertiary consumers.

Can you recall?

Question 1.
Which factors do you find in your surroundings?
Answer:
In our surroundings there are abiotic and biotic factors. The biotic factors are animals and plants in the surroundings. The invisible bacteria and fungi also have important role in the ecosystem as decomposers. Important abiotic factors are air, water, land, sunlight, etc.

Question 2.
Are these factors directly or indirectly related to you?
Answer:
We are directly or indirectly connected to every single factor in the surrounding in which we reside. For the requirement of food, we are dependent on plants and animals. For our survival we continuously need oxygen, water and other minerals, etc.

Classify:

Question 1.
Classify the following into living and non-living factors. Sunlight, Sunflower, Elephant, Lotus, Algae, Stone, Grass, Water, Ant, Soil, Cat, Fern, Air, Lion.
Answer:

Living Factors	Non-living Factors
Sunflower, Elephant, Lotus, Algae, Grass, Ant, Cat, Fern, Air, Lion.	Sunlight, Stone, Water, Soil, Air.

Can you tell?

Question 1.
What is the role of microbes in above interaction?
Answer:
Microbes play the role of decomposers in the above interactions.

Question 2.
How do producers obtain abiotic factors?
Answer:
Producers obtain solar energy from sunlight. The other nutrients are obtained from soil, water and air.

Question 3.
From where do the consumers get their food?
Answer:
Consumers get their food from producers and other consumers.

Project:

Question 1.
Visit an ecosystem nearby, List the biotic and abiotic factors in it. Show with pictures or sketches, how they are dependant on each other.

Question 2.
With the help of internet find out the loss of ecosystems due to wars or atomic explosions. Describe in your words.

Class 8 Science Chapter 18 Ecosystems Important Questions and Answers

Complete the following by using the correct option:

Question 1.
Biotic community is another name for ………. (ecology, ecosystem, population)
Answer:
Biotic community is another name Biotic for ecosystem.

Question 2.
Microbes in an ecosystem are ………… (producers, consumers, decomposers)
Answer:
Microbes in an ecosystem are decomposers.

Question 3.
Many types of ecosystems are found in ………… (oceans, deserts, biosphere)
Answer:
Many types of ecosystems are found in biosphere.

Question 4.
………….. is a type of grassland ecosystem. (Taiga, Tundra, Desert)
Answer:
Taiga is a type of grassland ecosystem.

Question 5.
Gir forest in Gujarat is the only habitat/shelter for the spectacular ………….. (Asiatic lion, Royal Bengal tiger, One-horned rhino)
Answer:
Gir forest in Gujarat is the only habitat shelter for the spectacular Asiatic lion.

Correct the following statements by changing one or two words:

Question 1.
Primary, secondary, tertiary consumers are the abiotic factors of the ecosystem.
Answer:
Primary, secondary, tertiary consumers are the biotic factors of the ecosystem.

Question 2.
Most of the ecosystems are simple.
Answer:
Most of the ecosystems are complex.

Question 3.
The word ecosystem was brought in the use by Ray Claffam.
Answer:
The word ecosystem was brought in the use by A.G. Tansle.

Question 4.
Specific ecosystem developed in a vast area is called a biosphere.
Answer:
Specific ecosystem developed in a vast area is called a biomes.

Question 5.
Longer summer and limited rain develop very tall plants in the grassland ecosystem.
Answer:
Longer summer and limited rain develop dwarf plants in the grassland ecosystem.

Question 6.
29 % of the earth surface is covered by water and only 71 % has land on it.
Answer:
71 % of the earth surface is covered by water and only 29 % has land on it.

Question 7.
Dams increase the water current in lower area.
Answer:
Dams lessen the water current in lower area.

Match the following:

Question 1.

Column ‘A’	Column ‘B’
1. The Great Himalayan National Park	a. Asiatic lion
2. Kaziranga	b. Tigers
3. Bharatpur	c. Aquatic birds
4. Ranthambore	d. One-horned Rhino
5. Gir forest	e. White panther

Answer:

Column ‘A’	Column ‘B’
1. The Great Himalayan National Park	e. White panther
2. Kaziranga	d. One-horned Rhino
3. Bharatpur	c. Aquatic birds
4. Ranthambore	b. Tigers
5. Gir forest	a. Asiatic lion

Find the odd one out:

Question 1.
Typha, Pistia, Eichhornia, Dipterocarpus
Answer:
Dipterocarpus. (All others are aquatic plants.)

Question 2.
Teak, Parthenium, Pine, Sandalwood
Answer:
Parthenium. (All others are forest trees.)

Question 3.
Giraffe, Zebra, Cheetah, Elephant
Answer:
Cheetah.. (All others are surviving grassland animals, Cheetah is a forest animal that is extinct from Asia.)

Question 4.
Hyena, Cow, Deer, Rabbit
Answer:
Hyena. (All others are primary consumers, Hyena is tertiary consumer.)

Question 5.
Fusarium, Leptocorsia, Aspergillus, Polycarpus
Answer:
Leptocorsia. (All others are decomposers, Leptocorsia is primary consumer.)

Taking into consideration the relationship in the first pair, complete the second pair :

Question 1.
Plants : Producers : : ……… : Consumers
Answer:
Animals

Question 2.
Secondary consumers : Jackals : : Tertiary consumer : ………..
Answer:
Kite/Lion/Hyena

Question 3.
Goat, sheep : Grassland ecosystem : : Tigers : …………..
Answer:
Forest ecosystem

Question 4.
Desert : Land biome : : Creek : …………….
Answer:
Aquatic biome

Question 5.
Limited rain : Grassland ecosystem : : ……….. : Tropical rainforests
Answer:
Excessive rain.

Answer in one sentence:

Question 1.
What is an ecosystem?
Answer:
The structure which is formed due to interactions between abiotic and biotic factors is called an ecosystem.

Question 2.
What is an ecological niche?
Answer:
The position of any living organism with reference to other living organisms and the role played by that organism is called ecological niche.

Question 3.
How are types of ecosystems formed?
Answer:
Types of ecosystems are formed according to size, place, climate, types of plants and animals that survive in that ecosystem.

Question 4.
Give examples of land biomes.
Answer:
Grasslands, evergreen forests, deserts, Tundra or polar ecosystem, ecosystems in Taiga, tropical rainforests, etc. are land biomes.

Question 5.
What are the reasons for tourism among the people?
Answer:
Tourism is mainly because people like to visit scenic places, undertake nature watch, wish to visit to sacred places and for entertainment purpose.

Question 6.
Why we should protect natural ecosystems?
Answer:
Natural ecosystems must be protected as they maintain balance in the biosphere.

Give my information Write short notes:

Question 1.
Dudhwa forest.
Answer:
Dudhwa forest is in Uttar Pradesh. About a century back, Dudhwa forest was the habitat for one-horned Rhino. However, due to hunting and poaching in 20th century, this animal became endangered. Thus to restore their populations, on 1st April 1984 rhino were introduced there again. Rhinos can were bred in captivity followed by releasing them back into natural ecosystem.

For this purpose at first the land was selected. This was 27 square km grassland and forest with continuous water supply through natural resources. Two observatories were established for making these efforts successful. Now Dudhwa is known for one¬horned Rhino population.

Question 2.
Aquatic ecosystems.
Answer:
Earth’s 71 % of surface is covered over by aquatic ecosystems. They are of three main types, viz. fresh water ecosystem, marine ecosystem and brackish water ecosystem. Rivers, lakes and ponds and streams are some of the fresh water ecosystem. Fresh water contains less salt and hence it is potable. Marine water has more salinity, i.e. its salt content is high. Brackish water ecosystem is present in the creeks. Here the saline and fresh water mix together. Hence salinity here is lesser than that of the marine water.

Give scientific reasons:

Question 1.
Microbes are called decomposers.
Answer:
Decomposition is the process in which the organic compounds are broken down to their inorganic constituents. The organic substances such as carbohydrates, proteins and lipids which are locked in the dead remains of plants and animals are converted into hydrogen, oxygen, calcium, iron, sodium, potassium, etc. by microbes. Therefore, microbes are called decomposers.

Use your brain power:

Question 1.
Which biotic factors get affected due to a dam?
Answer:
The biotic factors include plants, animals and humans. Lot of vegetation is submerged from the place where dam is constructed. The forests are wiped out. Large scale deforestation takes place in the proposed dam area. Wildlife is destroyed completely. The resident animals whose habitat are there either migrate away or are killed due to lack of their food and shelter. Many instances of animal-human conflicts arise when the wild animals drift to the neighbouring human settlements.

If human settlements are shifted, people are displaced. They lose their houses and agricultural land. Though compensation is given to them, there is great change for the people. Water current in lower area of the dam is reduced due to construction of dam-walls. Therefore, the original lotic (running 5 water) ecosystems that were present are destroyed after the construction of dam.

Question 2.
What will be the effects on biotic factors in the running water of river?
Answer:
The aquatic flora (plants) and fauna (animals) are well adapted to their habitats. The running water ecosystems are known as lotic ecosystems. The non-moving waters on the contrary create lentic ecosystems. Lotic ecosystems provide special adaptations to the plants and animals living therein. Plants are mostly in the form of freely floating algae and phytoplankton. Animals are well adapted for swimming in the currents of water. The fishes especially show a stream-lined body, fins for swimming, and gills to take up dissolved oxygen in the water. The other animals are also well adapted to the currents of water.

Think about it:

Question 1.
Can we call a tree an independent ecosystem?
Answer:
The huge tree can be an independent ecosystem. On one such tree there may be different habitats. Variety of insects thrive on huge tree by making their habitats in cracks and crevices on the tree. Many birds visit the tree to feed on such insects. There are many bird species that live in the hollow of the tree. Garden lizards, chameleons, snakes are the different reptiles seen associated with the tree ecosystem.

Squirrels, rabbits, bats are the mammals which take shelter in and around the trees, also inhabit a tree variety of fungi, lichens, mosses and epiphytic plants like orchids survive on the huge trees. Many food chains and complicated food webs are formed with the support of the tree. Thus one can say that a tree is an independent ecosystem.

Question 2.
Today Divija visited a hill. Honey: bees were hovering on flowers. One of them stung Divijia’s hand. Divija was hurt due to that sting and said with anger that all the honey-bees from the whole world must get destroyed. Afterwards, she thought what will happen if all honey-bees are destroyed? We will get honey, nothing more. What would be your explanation to Divija?
Answer:
Honey bees provide us with honey and bee-wax. Both of these are commercial products. But more than that the role played by honey bees in the pollination of flowers is very important. Due to their nectar collecting behaviour, they bring about pollination of the flowers.

Presence of honey bees is thus very essential for the agriculture and horticulture. Without honey bees, the growth of fruits and grains will not be possible, if pollination and subsequent fertilization does not take place in nature. This will create famine-like conditions. Therefore, honey bees’ position in the nature is very important.

Chart based questions:

Question 1.
Complete the following chart in context to a grassland.

Answer:

Question 2.
Write the information about various components of forest.

Answer:

Question 3.
Observe such ecosystems around you and complete the following chart.

Answer:

Question 4.
Complete the table.

Answer:

National Park/Sanctuary	State
1. Gir	Gujarat
2. Dachigam	Jammu-Kashmir
3. Ranthambore	Rajasthan
4. Dajipur	Maharashtra
5. Kaziranga	Assam
6. Sunderbans	Bengal
7. Melghat	Maharashtra
8. Periyar	Kerala

Question 5.
Complete the following chart:

Answer:

Diagram based questions:

Question 1.
Correct the following diagram:

Answer:

MCQs based on experiment:

Question 1.
Which one out of the following is not biotic factor?
(a) Humidity
(b) Rabbit
(c) Snake
(d) Bacteria
Answer:
(a) Humidity

Question 2.
Which climatic factor is causing migration of the birds in certain regions of the earth?
(a) Humidity and rainfall
(b) Ambient temperature
(c) Amount of carbon dioxide
(d) Amount of plant matter
Answer:
(b) Ambient temperature

Question 3.
Which abiotic factor mainly distinguishes marine water from the fresh water?
(a) Temperature
(b) Dissolved oxygen:
(c) Salinity
(d) Surface tension
Answer:
(c) Salinity

Question 4.
Why is creek water different from the river water?
(a) Creek water is more polluted than the river water.
(b) Creek water is less salty than the river water.
(c) Creek water is more saline than the river water.
(d) Creek water is less turbulent than the river water.
Answer:
(b) Creek water is less salty than the river water.

Question 5.
Which land biome shows presence of cacti plants more?
(a) Polar regions
(b) Grasslands
(c) Rainforest
(d) Desert
Answer:
(d) Desert

Projects:

Collect information

Question 1.
What are the possible threats to grasslands?
Answer:
Man tries to use grasslands for agricultural purpose. This transformation causes loss of natural ecosystem. Many animals from grasslands are killed by hunting and poaching. Though now Wildlife Act has protected these animals, many wildlife species are already extinct. There are chances of forest fires which is the greatest threat to grasslands. The global warming may also cause grasslands to become a desert.

Question 2.
Why did Asian Cheetah become extinct in last century?
Answer:
When British ruled India, Asian Cheetah was hunted to a great extent. The kings and British rulers did rampant hunting. The forest lands were also reduced due to encroachment by humans to build their settlements. Dams were constructed. Mega highways, bridges and roads caused loss of habitat for Asian Cheetah. Cheetah needs large thickly forested territory. This was lost due to all man-made activities. All these reasons made Asian Cheetah extinct in last century.

Question 3.
Observe Asian Cheetah on internet. Describe it.
Answer:
Cheetah is the fastest running feline animal on the earth. Though from Asian regions it is said to be extinct, in African grasslands, its occurrence is still there. But it is endangered animal. By 2016, the global cheetah population is estimated at approximately 7,100 individuals in the wild. Several African countries have taken steps to improve cheetah conservation measures.

Cheetah has a slender body, deep chest, spotted coat. Its head is small rounded and on the face there is black tear-like streaks. It has long thin legs and a long spotted tail. Cheetah in India were tamed during Moghul period for assisting in hunting. Stories about such episodes are commonly told. However, the last Cheetah in India was spotted in Bastar, M.P. in 1948.

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 17 Man-made Materials Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 8 Science Solutions Chapter 17 Man-made Materials

Class 8 Science Chapter 17 Man-made Materials Textbook Questions and Answers

1. Try to find it:

Question a.
Plastic shows …………. property, hence it can be moulded to any shape.
Answer:
Plastic shows plasticity property, hence it can be moulded to any shape.

Question b.
Motor cars are coated with ……… .
Answer:
Motor cars are coated with Teflon.

Question c.
Thermocol melts at ………… °C.
Answer:
Thermocol melts at more than 100 °C (it is about 240 °C).

Question d.
…………….. glass dissolves in water.
Answer:
Alkali silicate or water glass dissolves in water.

2. Who is my partner?

Question a.

Column ‘A’	Column ‘B’
1. Lead glass	a. Plates
2. Bakelite	b. Mattresses
3. Thermocol	c. Electric bulb
4. Optic glass	d. Electric switch
5. Polypropylene	e. Lens

Answer:

Column ‘A’	Column ‘B’
1. Lead glass	c. Electric bulb
2. Bakelite	d. Electric switch
3. Thermocol	a. Plates
4. Optic glass	e. Lens
5. Polypropylene	b. Mattresses

3. Answer the following.

Question a.
Thermocol is produced from which material?
Answer:
Thermocol is made from polystyrene which is also a complex thermoplastic substance.

Question b.
Write uses of PVC.
Answer:
PVC or Polyvinyl chloride is used for making bottles, raincoat, pipes, handbags, shoes, electric cable insulation, furniture, ropes, toys, etc.

Question c.
Write the natural or man-made raw material of the following items.
Mattress, beaker, bangle, chair, gunny bag, broom, knife, pen.
Answer:

Items	Natural raw material	Man-made raw materials
Mattress	Cotton, Coir (Jute fibres)	Polypropylene
Beaker	___	Glass (Silicate or borosilicate glass)
Bangle	Gold, silver, lac, copper	Plastic, Glass
Chair	Wood	Plastic (PVC)
Gunny bag	Jute, cotton	Plastic (PVC)
Broom	Plant fibres	Plastic fibres (PVC)
Knife	Metals such as iron	Plastic
Pen	Metals	Plastic

Question d.
Which are the main ingredients of glass?
Answer:
The main ingredients of glass are sand and silica.

Question e.
How the plastic is produced?
Answer:

1. Plastics are derived from natural materials such as natural gas, oil, coal, minerals and plants.
2. The first synthetic plastics were i derived from cellulose, a substance found in plants and trees. This cellulose was heated with chemicals and resulted in a plastic like material.
3. In modern times, the different raw materials are used for making plastics, but most plastics are made from the hydrocarbons present in the natural gas, oil and coal.
4. Plastics are simply chains of like molecules linked together. These chains are called polymers. Thus, many plastics begin with “poly,” such as polyethylene, polystyrene and polypropylene.
5. These polymers are made of carbon and hydrogen and sometimes oxygen, nitrogen, sulphur, chlorine, fluorine, phosphorous or silicon.
6. Plastic is produced in factories by suitable chemical reactions.

4. Distinguish between. 

Question a.
Man-made material and natural material
Answer:

Man-made material	Natural material
1. The man-made materials are obtained from processes in scientific laboratory.	1. Natural materials are obtained from nature.
2. Man-made materials are subjected to rigorous processing to alter the material for serving the intended purpose.	2. Natural materials are subjected to less treatment and processing.
3. Man-made materials are typically much more durable having a very long lifespan.	3. Natural materials have shorter lifespan, because these materials were once alive and so gradually perish over time.
4. Maintaining man-made materials require less care and attention.	4. Maintaining natural materials requires lots of care and continuous attention.
5. Man-made materials can have a negative environmental impact because they are not sustainable. E.g. Glass, plastic, Thermocol, soil, metals, rubber.	5. Natural materials do not have a negative environmental impact because they can be degraded easily. E.g. Cotton, silk, wood.

Question b.
Thermoplastic and Thermosetting plastic:
Answer:

Thermoplastic	Thermosetting plastic
1. The plastic that can be moulded as per our wish is called thermoplastic.	1. The plastic in which a specific shape is given with the help of mould and this shape cannot be changed again on heating is called thermosetting plastic.
2. Thermoplastic substances can be recycled and reused. E.g. PVC – Polyvinyl chloride, PS – Polystyrene, PE – Polyethylene and PP – Polypropylene are types of thermoplastics.	2. Thermosetting plastic cannot be reused again. E.g. Bakelite, Melamine, Polyurethane and polyster are the types of thermosetting plastics.

5. Answer the following in your own words.

Question a.
Explain the effect of following materials on environment and human health.
1. Plastic
2. Glass.
3. Thermocol.
Answer:
1. Plastic:

1. Plastic is non-degradable substance. Hence if thrown in any ecosystem, it remains unchanged for many years.
2. It is one of the worst environmental pollutants as its disposal is a major problem.
3. If thrown in water bodies, it affects the aquatic animals. Many of turtles mistake it for algae and eat the plastic. Eventually such animals die due to choking.
4. In terrestrial environment, the grazing animals like cattle are affected due to plastic.
5. If burnt it emits very toxic gases.
6. In landfill sites, it remains unchanged for thousands of years.

2. Glass:

1. The glass production is carried out at high temperatures of about 1500 °C. This burning emits many hazardous gases like sulphur dioxide, nitrogen dioxide, carbon dioxide. These gases cause the greenhouse effect.
2. Moreover, glass being non-degradable, cause pollution.
3. If broken glass pieces or any waste glass material is disposed into aquatic environment, it affects animals and plants.
4. Similarly, glass pieces block the drainages.
5. The waste glass thrown anywhere cause injury to terrestrial fauna.

3. Thermocol:

1. Thermocol contains carcinogenic ingredients in the form of styrene. If there is prolonged contact with thermocol, there is a possibility of blood cancer like leukemia and lymphoma.
2. Thermocol is non-degradable. It cannot be degraded into harmless substances easily.
3. If it is burnt for destruction, it releases toxic gases in atmosphere.
4. The plates and cups used for food, water, tea, etc. are made up of thermocol. This may affect the health. Reheating the food kept in thermocol releases styrene. This styrene may dissolve in that food, causing health problems like cancer.

Question b.
Which measures will you arrange to minimize the environmental problems arising due to non-degradable plastic?
Answer:

1. The use of plastic should be minimum. Reducing the consumption, reusing the same plastic again and again, recycling the used plastic and making some new products from the used plastic are some of the measures that can be adopted.
2. There are attempts to use plastic in making roads. Therefore, plastic is bought with good price at some places.
3. Therefore, instead of disposing of it anywhere, it should be collected and sold in best possible way.
4. The better alternatives for plastic should be adopted.
5. The awareness programmes about misuse of plastic should be arranged so that common man can understand the dangers of using plastic.

6. Write short notes. 

Question a.
Glass production:
Answer:
The general preparation of the glass is as follows:

1. Mixture of sand, soda, lime and small quantity of magnesium oxide is heated in furnace.
2. At 1700 °C sand or silicon dioxide melts.
3. To make the mixture melt at lesser temperature, pieces of discarded glasses are added to it.
4. This addition makes the mixture to melt at lesser temperature of 850 °C.
5. When all the ingredients of mixture are liquified, then again it is heated up to 1500 °C.
6. This heating is immediately followed by cooling.
7. The sudden cooling causes the mixture to become homogeneous, amorphous and transparent instead of crystalline.
8. For variety of glass types, different proportions of ingredients are used for heating.

Question b.
Optic glass:
Answer:

1. Optic glass or optical glass needs to be very clear and transparent as it is used in spectacles, lenses and other devices like microscopes.
2. Optic glasses are produced from the mixture of sand, soda, limestone, barium oxide and boron.

Question c.
Uses of plastic:
Answer:
Plastic, the man-made material is used in various forms in modern age. According to the type of plastic, its uses are different.

I. Thermoplastic materials are used for manufacturing following articles:

1. Polyvinyl chloride or PVC is used to make bottles, raincoat, pipes, handbags,: shoes, electric cable insulation, furniture, ropes, toys, etc.
2. Polystyrene is used in making thermo insulating parts of electric appliances like refrigerators, gears of machines, toys, protective coverings like covers of CD and DVD, etc.
3. Polyethylene (PE) plastics are used for making milk bags, packing bags, flexible garden pipes, etc.
4. Polypropylene (PP) is used in making parts of loudspeakers and vehicles, ropes, mattresses, laboratory appliances, etc.

II. Thermosetting plastic is used in the manufacturing of the following items:

1. Bakelite for making cabinets of radio, T.V., telephones, electric switches, toys, plastic handles of cookers, etc.
2. Melamine for making domestically useful items like cup – saucers, plates, tray, some spare parts of airplane engines, electric and sound insulating coverings, etc.
3. Polyurethane in making surfing boards, small boats, furniture, seats in vehicles, etc.
4. Polyester in fibreglass, toners of laser printers, textile industry, etc.

Can you tell?

Question 1.
Make a list of 20 different man-made materials present in your home, school and places around and discuss.
Answer:
Schoolbag, books, computer, table lamp, tube lights, benches, shoes, dress, pencil, pen, tiffin box, water bottle, raincoat, umbrella, medicine tablets, pen drive, chalk, duster, utensils, gas burner, biscuits.

Can you recall?

Question 1.
How many plastic carry bags are brought in your home in a day? What happens to those later on?
Answer:
Till May 2018 about one or two plastic bags were brought in our home every day. But now due to prohibition on plastic bags and other plastic items by the Government, the use of plastic has been drastically reduced. The bags brought at home caused lot of plastic pollution. Plastic is non-biodegradable, thus it always created problem of their disposal.

If dumped in a water body, it can be hazardous for aquatic animals. If thrown in the garbage, plastic articles find their way to landfilling areas. If thrown anyhow plastic may be consumed by stray animals. This causes toxic effects on them. If burnt they emit toxic gases.

Question 2.
How are the used up and thrown away carry bags, water bottles, milk bags recycled?
Answer:
The plastic waste is collected by the kabadiwala or sweepers. They sell these articles to the recycling units. In recycling units, the recycling of some of the plastic items is done. This leads to formation of plastic of low quality which may be used in making some newer plastic items.

Question 3.
Which material is wrapped around the items of glass or similar material during transport to prevent from breaking up?
Answer:
The plastic bubble wrap or thermocol is used to protect fragile items from the shocks and breaks during their transport.

Project:

Question 1.
Collect the information about the plastic used in production of utensils used in microwave oven.

Question 2.
Collect the information about the material used in production of denture. (A set of artificial teeth)

Class 8 Science Chapter 17 Man-made Materials Important Questions and Answers

Try to find it:

Question 1.
The plastic that can be moulded as per our wish is called …………… .
Answer:
The plastic that can be moulded as per our wish is called thermoplastic.

Question 2.
…………… is a type of plastic used for manufacturing artificial teeth.
Answer:
Polyacrylic is a type of plastic used for manufacturing artificial teeth.

Question 3.
Thermocol is a form of a complex material called ……………. .
Answer:
Thermocol is a form of a complex material called polystyrene.

Write whether the following statements are True or False: Rewrite the false statements after correcting:

Question 1.
Plastics are inorganic polymers that show plasticity.
Answer:
False. (Plastics are organic polymers that show plasticity.)

Question 2.
Polythene, PVC are thermosetting plastic materials.
Answer:
False. (Polythene, PVC are thermoplastic materials.)

Question 3.
Plastic is bad conductor of heat and electricity.
Answer:
True.

Question 4.
Surfing boards are made up of bakelite.
Answer:
False. (Surfing boards are made up of polyurethane.)

Question 5.
Being bad conductor of electricity, glass is used as insulator in electric appliances.
Answer:
True.

Match the columns:

Question 1.

Column A	Column B
1. Borosilicate glass	a. Oxide of specific metal.
2. Alkali silicate glass	b. Sand, soda, limestone, barium oxide and boron.
3. Lead glass	c. Sand and soda.
4. Optical glass	d. Sand, soda, limestone and lead oxide.
5. Coloured glass	e. Sand, soda, boric acid and aluminium oxide.

Answer:

Column A	Column B
1. Borosilicate glass	e. Sand, soda, boric acid and aluminium oxide.
2. Alkali silicate glass	c. Sand and soda.
3. Lead glass	d. Sand, soda, limestone and lead oxide.
4. Optical glass	b. Sand, soda, limestone, barium oxide and boron.
5. Coloured glass	a. Oxide of specific metal.

Find the odd one out:

Question 1.
Bakelite, Melamine, Polystyrene, Polyester.
Answer:
Polystyrene (All others are thermosetting plastic materials, polystyrene is thermoplastic.)

Question 2.
Polyvinyl chloride, Polystyrene, Polypropylene, Polyurethane.
Answer:
Polyurethane (All others are thermoplastic materials, polyurethane is thermosetting plastic.)

Question 3.
Vegetable peels, Cotton bolls, Wooden scraps, Plastic bag.
Answer:
Plastic bag (All others are degradable materials, plastic is non-degradable.)

Question 4.
Teflon, Polyacrylic, Fibreglass, Polyester.
Answer:
Fibreglass (All others are types of plastic.)

Considering the relationship in the first pair, complete the second pair:

Question 1.
Processed glass: Fen glass : : Alkali silicate glass : ………..
Answer:
Water glass

Question 2.
Ferrous oxide: Bluish green glass : : Copper oxide : ……..
Answer:
Red glass

Question 3.
Lens : Optical glass : : Laboratory glassware : ……….
Answer:
Silica glass

Question 4.
Light bulbs, Tubes: Lead glass : : Medicine storing : ………
Answer:
Borosilicate glass

Question 5.
Glass: Mixture of silica and silicate : : Thermocol : ………..
Answer:
Polystyrene.

Distinguish between:

Question 1.
Degradable and Non-degradable substances:
Answer:

Degradable substances	Non-degradable substances
1. The substances which can be naturally reduced into their inorganic constituents are called degradable substances.	1. The substances that cannot be degraded on their own into their inorganic constituents are called non-degradable substances.
2. Degradable substances are not accumulated in the nature.	2. Non-degradable substances remain accumulated in the nature for a long time.
3. Degradable substances emit foul odour when they are being decomposed.	3. Non-degradable substances may not emit foul odour as they are not degraded. But they make the place look dirty.
4. Usually microorganisms play a part in the degradation process, hence such substances are also called biodegradable. E.g. Vegetables, fruits, wood, cotton or wool fibres, etc.	4. Microorganisms cannot act on non-degradable substances and hence they are also called non-biodegradable substances. E.g. Plastic, thermocol, glass, metals, etc.

Write short notes:

Question 1.
Properties of plastic:
Answer:

1. Plastic is non-corrosive.
2. It is non-degradable as it does not decompose.
3. The factors such as humidity, heat, rain, etc. do not affect plastic.
4. Any coloured item can be manufactured from plastic.
5. Plastic shows property of plasticity. Thus it can be moulded into any shape that is needed.
6. Plastic is a bad conductor of heat and electricity.
7. Plastic is light-weight and thus preferred for carrying.

Question 2.
Properties of Glass:
Answer:
The glass becomes soft on heating and thus can be moulded into desired shape.

1. According to ingredients added at the time of preparation of glass, its density changes accordingly.
2. Glass is slow conductor of heat. If a cold glass is quickly heated, it cracks suddenly. Similarly, the warm glass if exposed to sudden cooling, it too cracks.
3. Glass is a bad conductor of electricity. Therefore, it is used as insulating material in electric appliances.
4. Glass is transparent, allowing most of light to pass through it. If there are chromium, vanadium or iron oxides in the glass, large amount of light is absorbed in glass.

Answer the following questions in one sentence only:

Question 1.
What is the use of plastic in healthcare sector?
Answer:
Saline bottles, pouches, blood bags, syringes and medicine bottles are made up of plastic, making plastic irreplaceable in the healthcare sector.

Question 2.
Which material is used in coating of vehicles? Why?
Answer:
Teflon is used for coating the vehicle as it protects the vehicles from scratches.

Question 3.
What is the use of polyacrylic type of plastic?
Answer:
Polyacrylic plastic used for manufacturing lenses and in the manufacture of artificial teeth.

Question 4.
What is 4R principle?
Answer:
The 4R principle is the way of behaviour that prevents or lessens the environmental pollution. The 4Rs are Reduce, Reuse, Recycle and Recover.

Question 5.
What are the eco-friendly options for a plastic bag?
Answer:
Jute bag, cloth bag and reusable bags of any natural materials are the eco-friendly options for the plastic bag.

Question 6.
How is Borosilicate glass produced?
Answer:
Borosilicate glass is produced by melting the mixture of sand, soda, boric acid and aluminium oxide.

Question 7.
When is large amount of light absorbed in the glass?
Answer:
If there are oxides of either chromium, vanadium or iron in the glass, large amount of light is absorbed in it.

Give scientific reasons:

Question 1.
It is harmful to eat food kept in thermocol.
Answer:
Thermocol is made up from polystyrene. It is carcinogenic (cancer causing) substance. When food kept in r thermocol containers is reheated, this , styrene dissolves in it. This may affect the r health of the person who consumes such food. It has been noted that there is a great possibility of blood cancer like leukaemia r and lymphoma if one remains in contact with thermocol for a longer time. Thus, it is harmful to eat food kept in thermocol.

Question 2.
Vessels used to cook food in the microwave oven are made up of plastic.
Answer:
The vessels made from metals cannot be used in the microwave oven. The microwaves cannot penetrate steel and so ‘ can only heat the contents through the open top. Some metals cause sparking with microwaves. Microwave energy is absorbed differently by different materials. Plastics of only certain kind are more suitable to be used in the microwave oven.

Answer the following:

Question 1.
What are the qualities of thermocol?
Answer:

1. Thermocol is modern man-made material made from polystyrene.
2. It can be transformed into liquid state when heated at more than 100 °C temperature. On cooling, it returns to the solid state.
3. Therefore, any desired shape can be given to it.
4. It acts as a good shock-absorber and hence used as a packing material to transport brittle material.
5. It is a bad insulator of heat and hence used for storing fish and other perishable articles in market.

Think about it:

Question 1.
Why are the plastic tanks used for storage of chemicals?
Answer:
Plastic is non-corrosive. It is comparatively non-reactive and it does not decompose. Moreover, the plastic containers are easier for handling. They are lighter and unbreakable. Hence the plastic tanks are used for storage of chemicals.

Question 2.
Why most of domestically useful items are replaced by plastic?
Answer:
Plastic is lighter and unbreakable. The handling thus becomes easier. It is non-corrosive, hence pickles, spices, etc. can be stored in plastic containers. It is cheaper as compared to the metal and glass articles. Thus, it becomes popular with general public. It is easier to wash and maintain the plastic articles. These are some of the reasons of making plastic a domestically useful material.

Collect information:

Question 1.
To prevent the degradation due to sunlight, some materials are stored in which type of bottles?
Answer:

The amber glass or brown coloured glass bottles are used to store the materials that may get degraded due to sunlight. This colour prevents the ultraviolet rays of the sun to enter the bottle and bring about chemical changes in the materials. Especially, for sensitive medicines, brown glass bottles are used.

Question 2.
Which type of glass is used in vehicles to avoid injuries in accidents?
Answer:
Front and rear doors have tempered glass. The windshield has laminated safety glass. Even if the accident takes place the glass pieces do not injure the passengers. Laminated safety glass combines two curved glass sheets and a plastic lamina between the two layers of the glass.

This glass is tough and protective. Tempered glass on the other hand is toughened glass which is processed by controlled thermal or chemical treatments. Upon breaking, the tempered glasses crumble into small granular chunks instead of splintering into sharp glass pieces. This prevents the injuries.

Sketch and label the diagram of glass manufacturing process:

Open-Ended Questions:

Question 1.
Classify and make a chart of the materials used in various items in house. Make additions to that chart with reference to various materials.

Answer:

Question 2.
Make list about use of thermocol in your daily life.
Answer:

1. Decorative items used at the time of festivals.
2. Packing materials.
3. Insulating boxes to keep food warm.
4. Insulating boxes to keep fish in iced condition to prevent decomposition.
5. Thermocol beads in the bean bags.

Balbharti Maharashtra State Board Class 8 Science Solutions Chapter 19 Life Cycle of Stars Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 8 Science Solutions Chapter 19 Life Cycle of Stars

Class 8 Science Chapter 19 Life Cycle of Stars Textbook Questions and Answers

1. Search and you will find:

Question a.
Our galaxy is called ………… .
Answer:
Our galaxy is called the Milky Way and Mandakini.

Question b.
For measuring large distances, ………… is used as a unit.
Answer:
For measuring large distances, the light year is used as a unit.

Question c.
The speed of light is …………. km/s.
Answer:
The speed of light is 300000 km/s.

Question d.
There are about ………… stars in our galaxy.
Answer:
There are about 100 billion stars in our galaxy.

Question e.
The end stage of the Sun will be …………. .
Answer:
The end stage of the Sun will be a white dwarf.

Question f.
Stars are born out of ………… clouds.
Answer:
Stars are born out of interstellar clouds.

Question g.
Milky way is a ………. galaxy.
Answer:
Milky way is a spiral galaxy.

Question h.
Stars are gigantic spheres of ………… gas.
Answer:
Stars are gigantic spheres of hot gas.

Question i.
The masses of other stars are measured relative to the mass of the …………. .
Answer:
The masses of other stars are measured relative to the mass of the Sun.

Question j.
Light takes ……………. to reach us from the Sun while it takes …….. to reach us from the moon.
Answer:
Light takes about 8 minutes to reach us from the Sun while it takes about 1 second to reach us from the moon.

Question k.
The larger the mass of a star, the faster is its ……….. .
Answer:
The larger the mass of a star, the faster is its evolution.

Question l.
The number of fuels used in the life of a star depends on its …………. .
Answer:
The number of fuels used in the life of a star depends on its mass.

2. Who is telling lies?

Question a.
Light year is used to measure time.
Answer:
False. (Light year is used to measure distance.)

Question b.
End stage of a star depends on its initial mass.
Answer:
True.

Question c.
A star ends its life as a neutron star when the pressure of its electrons balances its gravity.
Answer:
False. (A star ends its life as a neutron star when the pressure of its neutrons balances its gravity.)

Question d.
Only light can emit from the black hole.
Answer:
False. (Not even light can be emitted by a black hole.)

Question e.
The Sun will pass through the supergiant stage during its evolution.
Answer:
False. (The Sun will pass through the red giant stage during its evolution.)

Question f.
The Sun will end its life as a white dwarf.
Answer:
True.

3. Answer the following question:

Question a.
How do stars form?
Answer:
There are huge clouds of gas and dust in the empty spaces between the stars in a galaxy. These clouds are called interstellar clouds. The size of an interstellar cloud is about a few light years.

When an interstellar cloud starts contracting due to some disturbance, its density and temperature increase. This results in formation of a dense sphere of hot gas and nuclear energy generation starts at the centre of the star. Therefore, the gas sphere becomes self-luminous. Thus a star is formed, i.e., a star is born.
A huge interstellar cloud can produce thousands of stars at a time.

Question b.
Why do stars evolve?
Answer:
Although stars appear stable for quite a long period of time, their properties do change, though very slowly. A change in the properties of a star, leading to its passing through different stages, is called evolution of the star. Burning of the fuel at the centre of the star and a gradual decrease in its amount is the main reason of evolution of a star.

Question c.
What are the three end stages of stars?
Answer:

1. Stars having initial mass less than 8 times the mass of the Sun ultimately become white dwarfs.
2. Stars having initial mass between i 8 and 25 times the mass of the Sun ultimately become neutron stars.
3. Stars having initial mass larger than 25 times the mass of the Sun ultimately turn into black holes.

Question d.
Why was the name black hole given?
Answer:
When a star having initial mass larger than 25 times the mass of the Sun reaches its end stage, its gravitational force and density increase exponentially. All nearby objects get attracted towards the star and nothing can come out of it, not even light. All incident light is absorbed by the star. We can probably see a very minute black hole at its place. Hence, the name is given as black hole.

Question e.
Which types of stars end their life as a neutron star?
Answer:
Stars having initial mass between 8 and 25 times the mass of the Sun end up as neutron stars. When these stars pass through ( the supergiant stage, their size increases to 1000 times. Huge explosion that occurs in the last stage of these stars is very powerful and very high energy is given off. After the huge explosion, called the supernova explosion, their central portion contracts in size to about 10 km. In this stage, such stars are completely made up of neutrons and hence are called neutron stars.

4. A. If you are the Sun, write about your properties in your own words.
B. Describe white dwarfs.

Question A.
If you are the Sun, write about your properties in your own words.
Answer:

If you are the Sun, write about your properties in your own words.
Answer:
There are billions of stars in the galaxy called the Milky Way and Mandakini. I am one of the small stars called the Sun. I have my own family called the solar system. There are planets, satellites, asteroids, comets and meteors in my family. My mass is 2 × 1030 kg which is about 3.3 lakh times that of the earth. With a radius of 695700 km, my size is about 100 times that of the earth. My surface temperature is about 5800 K while it is 1.5 × 107 K at the centre.

72 % of my mass consists of hydrogen while 26 % consists of helium. Rest 2 % is made up of elements heavier than helium. I am about 4.5 billion years old and the scientists on the earth have concluded that not much change has taken place in my properties during this period. According to the scientists, in the end stage of my life, I will turn into a red giant star. Thereafter, I will first explode and then contract to become as small as the earth. I will appear small as well as white and hence, I will be called a white dwarf. This will be my last stage for ever.

Question B.
Describe white dwarfs.
Answer:
Depending on the initial mass, stars can reach one of the three end stages. White dwarf is one such stage of stars having initial mass less than 8 times the mass of the Sun. These stars undergo huge expansion and their radius increases by a factor of 100 to 200. These stars appear reddish because of their large size and lower temperature. Hence, these stars are also called red giant stars.

At the end of their evolution, these stars explode, their outer gas envelope is thrown outward and the inner part contracts to the size of the earth. However, the density in the star becomes very high. In this stage, the pressure due to electrons becomes independent of temperature and sufficient to balance the gravitational force for ever.

In this stage, such stars look white and due to their small size they are called white dwarfs.

Can you recall?

Question 1.
What is a galaxy?
Answer:
A system of billions of stars, their planetary systems and interstellar clouds of gas and dust held together by gravitational attraction is called a galaxy.

Question 2.
What are the different constituents of our solar system?
Answer:
The different constituents of our solar system are as follows :

1. Sun as a star.
2. Eight planets, namely, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune; of which Mercury, Venus, Earth and Mars are made up of rocks and minerals, while Jupiter, Saturn, Uranus and Neptune are made up of gases.
3. Natural satellites of some planets revolving around the respective planets.
4. Asteroids located between Mars and Jupiter.
5. Comets made up of ice, dust and gases.
6. Meteors and meteoroids.

Question 3.
What are the major differences between a star and a planet?
Answer:

1. Nuclear/atomic explosions regularly take place at the centre of stars. This causes the discharge of heat and light. Hence, stars shine. Planets do not discharge any light. They are visible due to the light reflected by them.
2. Stars are very big in size and massive relative to planets.
3. Stars twinkle, planets do not.
4. Stars are made up of hydrogen, helium and other light elements.
5. Planets are made up of solid, liquid or gaseous substances or a combination thereof.

Question 4.
What is a satellite?
Answer:
An astronomical object orbiting a planet is called a satellite.

Question 5.
Which is the star nearest to us?
Answer:
The star nearest to us is the Sun.

Project:

Question 1.
Use your imagination and make models of the Milky Way and the solar system.
Answer:
N.B. Students can make these models and display the same in science exhibition. You can use sand, scrap material, stones, pebbles, marbles, pieces of glass, beads, etc.

Question 2.
Write the effects: If the Sun disappears ………..
Answer:
N.B. You can write the effects with the help of the following points:

1. No sunrise, no sunset, no beauty of morning and evening wee hours.
2. In the absence of the gravitational force due to the Sun, the earth will drift away in the galaxy.
3. Darkness, no source of energy, end of life on the earth.
4. Moon will be invisible.
5. The temperature of the earth will fall below the freezing point of water. All oceans will also freeze.
6. Even the atmosphere will freeze and fall on the earth. This will cause more cosmic rays to reach the earth.

Class 8 Science Chapter 19 Life Cycle of Stars Important Questions and Answers

Match the columns:

Question 1.

Column ‘A’	Column ‘B’
1. Gravitational force	a. Alpha Centauri
2. The star nearest to us other than the Sun	b. 2 × 1030 kg
3. Mass of the Sun	c. 10 30 g
	d. towards the centre of a star or a planet

Answer:

Column ‘A’	Column ‘B’
1. Gravitational force	d. towards the centre of a star or a planet
2. The star nearest to us other than the Sun	a. Alpha Centauri
3. Mass of the Sun	b. 2 × 1030 kg

Question 2.
Mass of the star:

Column ‘A’	Column ‘B’
1. < 8 MSun	a. Proton star
2. between 8 and 25 times MSun	b. Black hole
3. > 25 MSun	c. Neutron star
	d. White dwarf

Answer:
Mass of the star:

Column ‘A’	Column ‘B’
1. < 8 MSun	d. White dwarf
2. between 8 and 25 times MSun	c. Neutron star
3. > 25 MSun	b. Black hole

Answer the following questions in one sentence each:

Question 1.
Name the star nearest to the earth.
Answer:
The Sun.

Question 2.
Other than the Sun, which is the star nearest to the earth?
Answer:
Alpha Centauri.

Question 3.
What would be the last stage of the Sun?
Answer:
The last stage of the Sun would be white dwarf.

Question 4.
Name two forces that act on any star.
Answer:
Gravitational force and the force due to the pressure of hot gas are the two forces that act on any star.

Question 5.
What is a black hole?
Answer:
A black hole is the end stage of a quite big star, where due to the extremely high gravitational force, nothing, not even light, comes out.

Answer the following questions:

Question 1.
How is stability of stars maintained?
Answer:
Properties of a star remain unchanged for quite a long time. The gravitational force and the force due to the pressure of the hot gas act together on a star. The gravitational force acts towards the centre of the star and tries to bring the gas particles close together. Hot gas shows the tendency to spread and its force acts away from the centre of the star. This force tries to disperse the gas particles. A balance between the gravitational force and the force due to the hot gas keeps the star stable.

However, if the magnitude of any one force is more than that of the other force, the star either contracts or expands depending upon which force dominates.

Question 2.
Why is the Sun called an ordinary star?
Answer:
The star nearest to the earth is the Sun. Hence, it appears quite big and bright. There are billions of stars in our galaxy called the Milky Way and Mandakini which are greater or lower in mass, size and temperature than the Sun. Hence, the Sun is called an ordinary star.

Do you know?

When the Sun will become a red giant, its diameter will increase so much that it will swallow Mercury and Venus. It is possible that the earth will also be absorbed by the Sun. It will take about 4-5 billion years for the Sun to reach this state.

Question 3.
Describe various stages of evolution of star.
Answer:
Though the properties of a star remain unchanged for quite a long time, this situation is never static. A star passes through different stages. This process is called the evolution of a star.
Important stages of the evolution of a star are as follows:

1. Initial stage of stability: The gravitational force and the force due to the pressure of the hot gas act together on a star. The gravitational force acts towards the centre of the star and tries to bring the gas particles close together. Hot gas shows the tendency to spread and its force acts away from the centre of the star.

This force tries to disperse the gas particles. A balance between the gravitational force and the force due to the hot gases keeps the star stable, as long as the energy generation continues at the centre of the star.

2. Burning of the fuel: As a star continuously emits energy, its energy constantly decreases. When the fuel at the centre of the star is exhausted, the energy generation stops and the temperature of the star starts decreasing. Decreasing temperature causes the gas pressure to decrease and the balance between the gravitational force and the force due to the gas pressure is no more maintained.

As the magnitude of the gravitational force is now more than that of the force due to the gas pressure, the star starts contracting. This causes another fuel to start burning, e.g. on exhausting hydrogen, helium starts undergoing fusion. Availability of multiple fuels depends on the mass of the star.

The higher the mass of the star, the more is the number of fuels used. The star either contracts or expands during the course of using these fuels. This may cause the imbalance between the gravitational force and the force due to the hot gas.

3. Total exhaustion of the fuel: When all fuels are exhausted, the energy generation in the star finally stops completely and the temperature of the star starts decreasing. The balance between the gravitational force and the force due to the gas pressure can no more be maintained. The evolution of the star ends and the star proceeds to its end stage.

4. End stage of a star: Once the fuel in the star is totally exhausted, the energy generation in the star stops and subsequently the gas pressure decreases, the star starts contracting and its density starts increasing. When the density becomes very high, some new types of pressures are generated which are independent of the temperature of the gas.

In such a case, the pressure remains stable despite low temperature and absence of any energy generation and thus the star remains stable for ever. This stage is the end stage of the star. Depending on the initial mass, stars can reach one of the three end stages.

• Stars having initial mass less than 8 times the mass of the Sun ultimately become white dwarfs.
• Stars having initial mass between 8 and 25 times the mass of the Sun ultimately become neutron stars.
• Stars having initial mass larger than 25 times the mass of the Sun ultimately turn into black holes.

Write short notes on the following:

Question 1.
End stages of stars having initial mass less than 8 times the mass of the Sun.
Answer:
These stars undergo huge expansion and their radius increases by a factor of 100 to 200 during their various stages of evolution. These stars appear reddish due to their lower temperature. Hence, they are called red giant stars.

At the end of evolution, these stars explode, their outer gas envelope is thrown out and the inner part contracts roughly to the size of the earth. Hence, the density of the star becomes very high. In this stage, the pressure due to electrons becomes independent of temperature and sufficient to balance the gravitational force for ever. Such stars look white and due to their small size they are called white dwarfs.

Question 2.
End stage of the stars having mass between 8 and 25 times the mass of the Sun.
Answer:
These stars pass through the red giant stage and later super giant stage, during which their size may increase to 1000 times. The huge explosion, called the supernova explosion, occurs in the last stage of the evolution. It is very powerful and very high energy is given off in this case.

As a result, the stars are visible even during the day. Later their central portion contracts to about 10 km. In this stage, the stars are completely made up of neutrons and are called neutron stars. The pressure of these neutrons is independent of temperature and sufficient enough to balance the gravitational force for ever.

Question 3.
End stages of stars having mass larger than 25 times the mass of the Sun.
Answer:
After the supernova explosion, no pressure can balance the gravitational force. Hence these stars contract continuously and their gravitational force and density increase exponentially. All nearby objects get attracted towards these stars and not even light can come out of them. Light falling on these stars is completely absorbed by the star. We cannot see these stars. A very minute black hole is formed at the place of such a star. This is the end stage of these stars.