Question

Electric bell works on the principle of _________

Answer 1

Electric bell:

1. A coil of wire is wound around a U-shaped iron piece, current flowing through the wire will make the iron piece temporarily magnetized.
2. Thus the iron piece ( electromagnet ) attracts a metal spring towards itself and when the hammer hits the gong we hear the sound.
3. When spring moves back, the circuit is open and no current flows through it.

Thus electric bell works on the principle of an electromagnet.