Question

a plastic rod becomes negatively charged when it is rubbed with a piece of wool. how does the rod become charged?
electrons move from the rod to the wool.
protons move from the rod to the wool.
electrons move from the wool to the rod.
protons move from the wool to the rod.

Explanation:

Charging by friction occurs when electrons are transferred. Protons are bound in the nucleus and don't move during such processes. When a plastic rod becomes negatively - charged by rubbing with wool, electrons move from the wool (which has a lower affinity for electrons) to the rod (which has a higher affinity for electrons).

Answer:

C. Electrons move from the wool to the rod.