What is electrification by friction?

• A. Heat generated by friction.
• B. Static electricity produced by rubbing two materials together.
• C. Light produced by friction.
• D. Electric current produced by a battery.

Answer: (B)

Electrification by friction is the buildup of static electricity on surfaces when two materials are rubbed together. The rubbing causes electrons to move from one material to the other because different substances hold onto electrons differently. The material that loses electrons becomes positively charged, while the one that gains electrons becomes negatively charged. These charges remain on the surfaces until they find a path to discharge, which is why you can see effects like a rubbed balloon sticking to walls or attracting lightweight paper. This is different from heat produced by friction, light produced by friction in some cases, or the continuous electric current produced by a battery.