Which process can remove electrons from objects by rubbing them together?

• A. Friction
• B. Conduction
• C. Induction
• D. Evaporation

Answer: (A)

Rubbing two different materials together can cause electrons to move from one object to the other. This is friction-induced charging, often called the triboelectric effect. The rubbing provides energy that helps electrons overcome their attachment to atoms, so electrons transfer and leave one object with a net positive charge and the other with a net negative charge. In everyday examples, rubbing a balloon on hair and sticking to a wall shows this effect. The other processes involve different ways charges move or appear: conduction is charge transfer by direct contact to even out charges, induction is rearrangement of charges due to a nearby charged object without actual transfer between objects, and evaporation is a phase change with no relation to charging. So the mechanism that removes electrons by rubbing is friction.