A negatively-charged plastic rod is brought close to (but does not touch) a neutral metal sphere that is connected to ground. After waiting a few seconds, the ground connection is removed
(without touching the sphere), and after that the rod is also removed. The sphere is now
A) neutral.
B) negatively charged.
C) positively charged.

Question

Quizplus · Accepted Answer

When a negatively charged rod is brought near a neutral metal sphere, electrons in the sphere are repelled away from the side closest to the rod due to repulsion. This leaves the side of the sphere nearest to the rod positively charged. If the sphere is grounded while this is happening, electrons will flow from the ground into the sphere to neutralize the positive charge on the side farthest from the rod, effectively removing some of the sphere's electrons. When the ground connection is removed, the sphere cannot regain the lost electrons, and when the rod is removed, the sphere remains positively charged because it has fewer electrons than protons.

A Negatively-Charged Plastic Rod Is Brought Close to (But Does