Explain the phenomenon of electromagnetic induction. Describe an experiment to show that a current is set up in a closed loop when an external magnetic field passing through the loop increases or decreases.

Electromagnetic Induction is defined as the process by which a changing magnetic field in a conductor induces a current in another conductor, is known as electromagnetic Induction.

An experiment to show that a current is set up in a closed loop when an external magnetic field passing through the loop increases or decreases is as follows:

1. Insert a coil over a hollow tube of a cardboard. With the wire connect the ends of the coil with a galvanometer.

2. Move the north pole of the magnet towards the end B of the coil

Observation: The galvanometer shows a deflection in the needle towards right direction

3. When Galvanometer is moved away from the coil

Observation: there is deflection in the galvanometer needle towards left direction.

4. When galvanometer is kept static

Observation: there is no deflection in the galvanometer.

This proves that when the coil and the magnet are brought in contact, a current is induced in the coil.