An electromagnet is used in an electric bell due to its ability to produce a magnetic field when an electric current flows through it, which is essential for the bell's operation.

In the case of an electric bell, when the switch is pressed, it completes the circuit, allowing current to flow through the coil of wire wrapped around a soft iron core, creating a magnetic field due to electromagnetic induction.

The magnetic field generated by the electromagnet attracts a nearby armature (a metal strip), which is connected to a hammer. This hammer strikes the bell or gong, producing sound.

Once the hammer strikes the bell, it breaks the circuit, stopping the current flow and causing the magnetic field to collapse. A spring mechanism then returns the hammer to its original position, allowing the circuit to reconnect if the button is still pressed, thus repeating the process rapidly and creating a continuous ringing sound.