Question

Given that Teflon rubbed with paper acquires a net negative charge, what is the sign of the charge on the electroscope that you charged by induction? What evidence do you have to support your answer?

Answer 1

Since Teflon rubbed with paper acquires a net negative charge, to understand this phenomena. Suppose a negatively charged object is brought near an uncharged electroscope. Electrons at the top are repelled and move to the leaves. Since the leaves are light and mobile, they move apart due to repulsion of like charges. The same happens if a positively charged object is brought near the electroscope, except that the electrons are attracted to the ball at the top and render the leaves positively charged, and therefore spread apart due to the repulsion.