Which of the following is a conductor of electricity?

Abdul was testing the conductivity of a few materials and kept different materials in the gap A - B. In which case did the bulb light?

Choose the correct reason.

Chemically inactive gases like argon and nitrogen are usually filled in a bulb. 

Choose the correct reasons for each.

A comb attracts bits of paper when combed through dry hair.

Choose the correct reason.

A body develops a negative charge.

Why should we wear rubber slippers while using a hairdryer?