Question

Describe a simple experiment using a pith ball electroscope to demonstrate that like charges repel and unlike charges attract each other.

Answer 1

1. To test the nature of a charge on a body (such as a glass rod rubbed with silk cloth), proceed as follows:
2. Take an uncharged pith ball electroscope.
3. Rub a glass rod with a silk cloth. The glass rod gets positively charged (you may take any other charged body).
4. Charge the pith ball positively by touching it with the charged glass rod.
5. Now bring the given charged body closer to the positively charged pith ball.
6. Observe the movement of the pith ball.
7. If the pith ball is repelled away from the given charged body, then the given charged body is positively charged.
8. This is because both, the pith ball and the given body, are positively charged and repel each other because like-charges repel each other.
9. If the pith ball is attracted towards the given charged body, then the given body may be either uncharged or negatively charged.