# Some Qustions of Electrostatic Induction

1. Oct 21, 2013

### rizwankhalil

Hi

Q 1 An electrified rod attracts pieces of paper. After a while these papers fly away. Why?

My Answer: Due to the phenomenon of electrostatic induction, the paper becomes charged and will be attracted towards the rod. After some time, the charge becomes neutral and paper flies.

Q 2 How much negative charge has been removed from a positively charged electroscope if it has a charge of 7.5 x 10-11 C?

My Answer: According to phenomenon of electrostatic induction, the amount of charge induces will be equal to amount of charge displaced. So - 7.5 x 10-11 C has been removed from a positively charged electroscope if it has a charge of 7.5 x 10-11 C.

Q 3 Rubber tires get charged from friction with the road. What is the polarity of the charge?

My Answer: Tires will acquire negative charges due to friction between Earth and tires. Electrons are transferred from Earth to rubber tires.

Q 4 Explain why, a glass rod can be charged by rubbing when held by hand but an iron rod can’t be charged by rubbing, if held by hands?

My Answer: Since glass is an insulator so when it is charged by rubbing, charges doesn’t move towards earth via human body. While iron is a conductor so when it is charged by rubbing, charges move towards the earth via human body.

Guide me in this regard.

Riz

2. Oct 21, 2013

### Crazymechanic

I'm not sure about the second but all the other ones are correct.

3. Oct 21, 2013

### Basic_Physics

Two is also right, but it is the law of conservation of charge.