I was watching someone use a pith ball electroscope. The guy charged an ebonite rod by rubbing it with fur ( got it ). As the ebonite rod was brought closer to the pith ball, the pith ball was attracted to the rod ( got it ). After touching the rod the ball got repelled which clearly indicates transfer of charge to the ball (HOW!).
I feel that ebonite is an insulator and the charges in it cannot move freely. So if I touch it with a conductor the charges must not get transferred but the experiment states otherwise.
Can somebody pls explain what I am doing wrong here ? Thx
Best Answer
Charges can be added or removed to or from the surface of an insulator. This is what the experiment shows. Insulators only inhibit the flow of charges in its volume or along its surface. Such an addition or removal of charge to or from the surface of an insulator is, e.g., used in electrostatic generators like the van de Graaff generator.