Question

Q:5 Draw a labelled diagram of electric bell


Write the construction and working of
electric bell.

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Answer 1

Working of the bell — Principle of working of electromagnetism When the switch is pushed on, the circuit gets completed and current stalls flowing through the U-shaped electromagnet which creates magnetic field in the core. This attracts the iron armature. Now when the armature moves towards the electro-magnet, the hammer strikes the gong and the bell rings. But as the armature

moves towards the electromagnet, the contact with the adjustment screw breaks which breaks the closed circuit and stops the current. Now when there is no current there is no electromagnetism and the armature returns to the original position. This making and breaking of the circuit of the electromagnet continues as long as the button remains pressed.

Answer 2

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• Draw a labelled diagram of electric bell
• Write the construction and working of electric bell.??

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• The electric bell works on the principle of the electromagnet. Its construction is shown in the above figure.

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 a magnet when current flows through it.

2. Striker in touch with 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.

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