Electrostatic Induction in Electroscope · PhysicsBowl 2011 #5
Physics · electromagnetism
Problem
A positively charged rod is brought near a metal electroscope that is initially uncharged. As shown in the figure, the rod does not touch the electroscope. There is no charge transfer between the electroscope and rod, but the leaves of the electroscope move apart from each other when the rod is brought near the top of the electroscope. Which one of the following choices is the best explanation for this phenomenon?
(A) Protons are repelled by the rod into the leaves of the electroscope.
(B) Electrons are attracted out of the leaves of the electroscope toward the rod.
(C) Protons are repelled into the leaves of the electroscope and electrons are attracted out of the leaves of the electroscope.
(D) Positively charged electrons are repelled by the rod into the leaves of the electroscope.
(E) Positively charged electrons are repelled into the leaves of the electroscope and regular electrons are attracted out of the leaves of the electroscope.