A student charges a balloon and then brings it near a metal sphere hanging from the
ceiling. She brings it near the sphere, but does not touch. The sphere moves toward
the balloon. What are the charges on the balloon and the metal sphere?
a) The balloon has a positive charge and the metal sphere has a negative charge.
b) The balloon has a negative charge and the metal sphere has a positive charge.
c) Both are negatively charged.
d) Both are positively charged.