Why is an electromagnet used in devices like electric bells?

An electromagnet is used in devices like electric bells because it can produce a temporary magnetic field only when electric current flows. This property allows precise control over its magnetic action.

In an electric bell, when current passes through the coil wound around an iron core, it becomes magnetized and attracts the iron armature. This movement causes the hammer to strike the bell. As the circuit breaks momentarily, the electromagnet loses its magnetism, and the armature returns to its original position. This cycle repeats rapidly, producing a continuous ringing sound.

The key advantage of using an electromagnet is that its magnetism can be switched on and off instantly, making it ideal for devices that require repeated motion.