Question

which of the following actions will cause a static charge to build up?
rubbing two materials together
mixing salt in water
placing a conductor in sunlight
connecting a circuit

Explanation:

Static charge builds up via friction. Rubbing two materials (like a balloon and hair) transfers electrons, creating static electricity. Adding salt to water (ionization, no static build - up), placing a conductor in sunlight (heat, not static - related), and connecting a circuit (current flow, not static build - up) don't cause static charge accumulation.

Answer:

A. Rubbing two materials together