Question

Draw a neat, labelled diagram of an electric bell and explain briefly how it works.

Accepted Answer

An electric bell has an electromagnet that pulls a strip of iron which makes the hammer hit the gong to ring the bell.

The working of an electric bell can be understood in three steps.

Step 1: When the switch of the bell is pressed, an electric current flows to the electromagnet.
Step 2: The electromagnet becomes magnetized and attracts the soft iron strip. The hammer attached to the strip then hits the gong, making it ring.
Step 3: When the soft iron strip gets attracted to the electromagnet, it no longer touches the screw (interrupter) and hence the circuit is broken. This turns off the electromagnet and it can no longer attract the soft iron strip. The soft iron strip returns to its initial position, touching the screw (interrupter). This results in the circuit being complete, and current flows again.

Steps 1 to 3 repeat in quick succession as long as the switch is on. This is how we hear a continuous ring of the bell.

Draw a neat, labelled diagram of an electric bell and explain briefly how it works.

Important Questions on Semester Test Paper (Chapters 11 to 18)

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