Answer to Question #146978 in Electric Circuits for Mae Chaela Demotor

Question

A positively charged rod attracts a small piece of cork.a) Can we conclude that the cork is negatively charged?b)The rod repels another small piece of cork. Can we conclude that this piece is positively charged?

Answer 1

a) we cannot conclude the cork is negatively charged. It might also be neutral. when the positively charged rod is brought close to the cork, the cork becomes charged by induction and acquires negative charges, so attraction will occur. Therefore, we cannot conclude that the cork was initially negatively charged.

b) If the rod repels another small piece of cork, we conclude that this piece is positively charged since repulsion occurs only between like charges.