How do charges behave in an alternating current?

Question

they move back and forth in a circuit
they flow in a positive direction only
they turn on and off repeatedly
they flow in a negative direction only

Answer 1

They move back and forth in a circuit. In an alternating current circuit, the flow of charges, which are typically electrons, regularly changes direction, oscillating back and forth at a specific frequency. This is what distinguishes AC from direct current (DC), where the flow of charges moves in one direction only.