Class 8 Science - Some Natural Phenomena

1. Which of the following cannot be charged easily by friction?

(b) A copper rod ✅
Copper is a metal and cannot hold charges by friction easily, unlike plastic or wool.

2. When a glass rod is rubbed with silk, what happens?

(b) becomes positively charged while the cloth has a negative charge ✅
Electrons move from the rod to the silk cloth, making the rod positive and the cloth negative.

3. True or False

(a) Like charges attract each other – ❌ False
(b) A charged glass rod attracts a charged plastic straw – ✅ True
(c) Lightning conductor cannot protect a building – ❌ False
(d) Earthquakes can be predicted – ❌ False

4. Why do we hear crackling sounds when removing woolen clothes?

It happens due to static electricity. Rubbing causes charge buildup, and the discharge makes a crackling sound.

5. Why does a charged object lose its charge when touched?

Our body allows electric charge to flow to the ground, so the charged object becomes neutral when touched.

6. What is the scale used to measure earthquake energy?

It is called the Richter scale. An earthquake measuring 3 is weak and recorded by a seismograph but causes little damage.

7. Suggest three safety measures during lightning.

• Stay indoors and avoid open fields.
• Do not use electrical devices.
• Stay away from trees and metal objects.

8. Why does a charged balloon repel another charged balloon?

Both balloons have the same type of charge, and like charges repel. An uncharged balloon gets attracted to the charged one.

9. Describe an instrument used to detect charge.

An electroscope is used. It has metal leaves that diverge when a charged object is brought near, showing the presence of charge.

10. Name three states in India where earthquakes are common.

• Jammu and Kashmir
• Uttarakhand
• Himachal Pradesh

11. What will you do if an earthquake strikes when you're outside?

• Move to an open area away from buildings.
• Stay away from trees and electric poles.
• Do not use elevators or go inside unstable structures.

12. Should you carry an umbrella if there’s a thunderstorm warning?

No, because metal rods in umbrellas can attract lightning. Stay indoors or use a raincoat if you must go out.