Establish the fact that the relative motion between the coil and the magnet induces an emf in the coil of a closed circuit.

Explanation

i. whenever the magnetic flux linked with a closed coil changes, an emf (electromotive force) is induced and hence an electric current flows in the circuit.
ii. This current is called an induced current called an induced emf. This phenomenon is known as electromagnetic induction.
iii. A bar magnet is placed close to a coil, some of the magnetic lines of forces of the bar magnet pas through the coil i.e., the magnetic flux is linked with the coil. When the bar magnet and coil approach each other, the magnetic flux linked with the coil increases.
iv. So this increases in magnetic flux induces an emf and hence a transient electric current flows in the circuit in one direciton. At the same time, when they recede away from one another, the magnetic flux linked with the coil decreases.
v. The decrease in magnetic flux again induces an emf in opposite direction and hence a electric current flows in the galvanometer when there is a relative motion between the coil and the magnet.