Unit - 5.3 Refraction Of Light — PHYSICS STD 8 — Question

Why does a plastic comb rubbed with dry hair attract bits of paper?

Write the correct statement :
When an electric current flows through an electric bulb, the electric energy first changes to light energy and then to heat energy.

Explain the following:Why do the army tanks move over the wide steel chain rather than on the wheels?

What determines the pitch of a sound?

Name a device which converts sound energy into electric energy?

Explain in brief why birds that walk on the leaves floating on the surface of water have wide feet.

Name the energy stored in a compressed spring.

When a charged rod is touched with the disc of a positively charged gold-leaf electroscope, it is observed that the divergence of leaves decreases. What is the kind of charge on the rod?

write the correct statement:
The molecules of a gas have very small intermolecular spaces.

Define kinetic energy and give an example of a body possessing kinetic energy.