Question

If a negatively charged rod is held near a neutral metal ball, the ball is attracted to the rod. This happens:_______

a. because of magnetic effects
b. because the ball tries to pull the rod's electrons over to it
c. because the rod polarizes the metal
d. because the rod and the ball have opposite charges

Answer 1

c. because the rod polarizes the metal.

Step-by-step explanation:

Bringing the negatively charged rod close to the neutral metal ball causes the neutral metal ball to be polarized with induced positive charge on it. The polarizing of the formally neutral metal ball is due to the negative charge on the metal rod (bodies induce a charge opposite of their own charge on a nearby neutral body). The ball and rod then attract themselves because bodies with opposite charges attract each other, unlike bodies with same charges that repel each other.