Which principle is used in the working of an electric bell?

An electric bell works on the principle of the magnetic effect of electric current.

When electric current flows through the coil, it creates a magnetic field, turning the iron core into an electromagnet. This electromagnet attracts the armature, causing the hammer to strike the bell.

As the armature moves, the circuit breaks momentarily, stopping the current. The electromagnet then loses its magnetism, and the armature returns to its original position. This process repeats rapidly, producing a continuous ringing sound.

Thus, the working of an electric bell is based on the conversion of electrical energy into mechanical motion using electromagnetism.