TextBook Solutions for Rajasthan Board of Secondary Education Class 8 Science Chapter 15 Some Natural Phenomena

Which of the following cannot be charged easily by friction?

• A copper rod

• A plastic scale

• An inflated balloon

• A woollen cloth.

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

• and the cloth both acquire positive charge.

• becomes positively charged while the cloth has a negative charge.

• and the cloth both acquire negative charge.

• becomes negatively charged while the cloth has a positive charge.

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

Like charges attract each other.

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

A charged glass rod attract a charged plastic straw.

Lightning conductor cannot protect a building from lightning.

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

Earthquakes can be predicted in advance.

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

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

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?

Suggest three measures to protect ourselves from lightning.