Answer:
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Components: 2 Mark
Working: 3 Marks
An electric bell consists of a coil of wire. An electromagnet wound on an iron piece. The coil acts as an electromagnet.
An iron strip with a hammer at one end is kept close to the electromagnet.There is a contact screw near the iron strip.
When the iron strip is in contact with the screw, current flows through the coil which becomes an electromagnet.
It, then,pulls the iron strip. In the process, the hammer at the end of the strip strikes the gong of the bell to produce a sound.
However, when the electromagnet pulls the iron strip, it also breaks the circuit. The current through the coil stops flowing and it isno longer an electromagnet. It no longer attracts the iron strip.The iron strip comes back to its original position and touches the contact screw again.
This completes the circuit. The current flows in the coil and the hammer strikes the gong again.
This process is repeated in quick succession.The hammer strikes the gong every time the circuit is complete. This is how the bell rings.