What is friction in electricity?

• A. The separation of charges within a material
• B. Rubbing two conductors together and the transfer of electrons charge between them
• C. The induction of charge by bringing a charged object near a conductor
• D. The flow of electrons through a conductor due to a potential difference

Answer: (B)

Friction in electricity means charging objects by rubbing them together, which causes electrons to move from one material to the other. Different materials have different tendencies to gain or lose electrons, and when they come into contact and are rubbed, electrons can transfer from the less-electronegative material to the more-electronegative one. The result is one object becomes negatively charged (gained electrons) and the other becomes positively charged (lost electrons). This is why rubbed objects like a balloon or a sock can attract light objects or stick to walls—the frictional contact created a static charge.

This isn’t about charges separating within a single object (that would be polarization), nor about rearranging charges without contact (induction), nor about continuous current flowing due to a voltage difference (that’s electric current). The essence of friction in electricity is the transfer of electrons that occurs when two materials are rubbed together.