Question

Describe the construction and working of an electric bell with the help of a diagram. 

Answer 1

Construction of an electric bell
Following are the components of an electric bell:

1. Electromagnet: A copper wire is wound around an iron piece, which acts as a magnet when current flows through it.
2. The striker is in touch with the contact screw through an iron strip.
3. A metal gong.
4. A key or a switch.

Working of an electric bell
When the switch is 'ON' and the screw is in contact with the iron strip, then electric current flows through the copper wire, which gets magnetised because of electromagnetism. This magnetised copper wire (or the electromagnet) attracts the iron strip towards it, letting the striker hit the gong, and thus sound is produced. As soon as the striker hits the gong, the screw loses its contact with the iron strip, and therefore, current stops in the circuit. At this point, the electromagnet loses its magnetism, and the iron strip moves back and comes in contact with the contact screw. The electric current is then restored in the circuit, and again the striker hits the gong by the above process. This action repeats itself, and the bell rings.