Some Natural Phenomena NCERT Solutions: Class 8 Science CBSE

Question 1

Sometimes, a crackling sound is heard while taking off a sweater during winters. Explain.

Question 2

Write T against true and F against false in the following statements.

(a) Like charges attract each other. (T / F)

(b) A charged glass rod attracts a charged plastic straw. (T / F)

(c) Lightning conductor cannot protect a building from lightning. (T/F)

(d) Earthquakes can be predicted in advance. (T / F)

Question 3

Explain why a charged balloon is repelled by another charged balloon whereas an uncharged balloon is attracted by another charged balloon?

Question 4

Describe with the help of a diagram an instrument which can be used to detect a charged body.

Question 5

Which of the following cannot be charged easily by friction?

(a) A plastic scale

(b) A copper rod

(c) An inflated balloon

(d) A woollen cloth

Question 6

When a glass rod is rubbed with a piece of silk cloth the rod

(a) and the cloth both acquire positive charge.

(b) becomes positively charged while the cloth has a negative charge.

(c) and the cloth both acquire negative charge.

(d) becomes negatively charged while the cloth has a positive charge.

Question 7

Explain why a charged body loses its charge if we touch it with our hand.

Question 8

Write T against true and F against false in the following statements.

(a) Like charges attract each other. (T / F)

(b) A charged glass rod attracts a charged plastic straw. (T / F)

(c) Lightning conductor cannot protect a building from lightning. (T/F)

(d) Earthquakes can be predicted in advance. (T / F)

Question 9

Suggest three measures to protect ourselves from lightning.

Question 10

The weather department has predicted that a thunderstorm is likely to occur on a certain day. Suppose you have to go out on that day. Would you carry an umbrella? Explain.

Question 11

Write T against true and F against false in the following statements.

(a) Like charges attract each other. (T / F)

(b) A charged glass rod attracts a charged plastic straw. (T / F)

(c) Lightning conductor cannot protect a building from lightning. (T/F)

(d) Earthquakes can be predicted in advance. (T / F)

Question 12

List three states in India where earthquakes are more likely to strike.

Question 13

Name the scale on which the destructive energy of an earthquake is measured. An earthquake measures 3 on this scale. Would it be recorded by a seismograph? Is it likely to cause much damage?

Question 14

Name the scale on which the destructive energy of an earthquake is measured. An earthquake measures 3 on this scale. Would it be recorded by a seismograph? Is it likely to cause much damage?

Question 15

Suppose you are outside your home and an earthquake strikes. What precaution would you take to protect yourself?

Question 16

What will happen if we hang a charged glass rod in place of the ebonite rod?

Question 17

True or false?

(a) When two substances are rubbed on each other, like charges are developed on each.

(b) An atom may have either a positive or a negative charge.

(c) Substances that allow the flow of electricity are called good conductors.

(d) If the leaves of the electroscope spread only a little, the charge on them is greater.

Question 18

Write answers the following questions.

(a) Why does friction cause a charge to develop?

(b) Why is the charge developed due to friction called a static electric charge?

(c) Why does the charge developed by induction disappear quickly?

(d) Why do the leaves of a gold leaf electroscope fly apart when a charged body touches its disc?

(e) What causes the cracking sound we hear as we wear a cardigan?

Question 19

Why are gold leaves used to make an electroscope more sensitive?

Question 20

What will happen if you touch the disc of the electroscope when its leaves are spread out?

Question 21

Match the following.

Group ‘A’

Group ‘B’

(a)

Glass road

1.

charged body

(b)

Ebonite rod

2.

positive charge

(c)

Lightning conductor

3.

negative charge

(d)

Electroscope

4.

lightning

Question 22

Why is a thick copper strip used in a lightning conductor?

Question 23

Why is a lightning conductor pointed?

Question 24

Why is a lightning conductor made of copper?

NCERT Question Solutions

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