Answer to Question #33881 in Electricity and Magnetism for Athul

Question

In A.C circuits electrons move back and forth and the net current over one complete cycle is zero.Then how does a bulb connected to an AC circuit glow as the same number of electrons flowing in flows out at next instant?

Answer 1

When the light bulb is connected to AC circuit, electronsare moving in the filament. Filament has high temperature. Electrons move back
and forth, but electrons move forth - stop - move back. Before the electrons change direction, electrons has moved slow. So, current is less. But we can't see this process. Why? Because filament has a thermal inertia, and light bulb can't cool down in a split second.