Question

Which instrument works on the principle of Electromagnetic induction?
(A) Electric motor
(B) Fuse
(C) Electric bell
(D) Electric generator

Answer 1

Hint
We know what electromagnetic induction is. We also know what is induced EMF and induced current. Using Fleming’s right hand rule, we will determine the direction of induced current. In the generator mechanical energy of a rotating conducting coil placed in a magnetic field is converted into electrical energy using the law of electromagnetic induction.

Complete step by step answer
Whenever the magnetic flux or total number of magnetic lines of force associated with an electric circuit or loop changes an EMF is produced in the circuit or the loop. This phenomenon is called electromagnetic induction.
The EMF produced is known as induced EMF.If the electric circuit is closed then the induced EMF sends a current, the current is known as induced current.
An electric generator is a machine which generates electricity by using the principle of electromagnetic induction. The electric generator is called dynamo.
When the coil rotates electromagnetic induction takes place. When the motion of one arm of the coil is downward, according to Fleming's right hand rule the current will be induced in the opposite direction. The reversal of the direction of current goes on periodically. Every time the coil crosses its vertical position, the direction of current gets reversed. The heating effect of electric current is independent on the direction of current. Lamp continues to glow as long as the coil rotates.
Hence the required solution is an electric generator (option- ‘D’).

Note
Electric motor rotates continuously when a force acts on a rectangular coil that is placed in a magnetic field and current is passed through it. The electric bell works on the principle of the