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

Explanation

Let us consider a closed circuit consisting of coil C insulated wire and a galvanometer G (figer a).The galvanometer does not indicate deflection as ther is no electric current in the circuit.
If a bar magnet is inserted in to the stationary coil, with its north pole facing the coil, then there is a momentary deflection in the galvanometer. This indicates that an electric current is set up in the coil (figure (b)).
If the magnet is kept stationary inside the coil, then the galvanometer does not indicate any deflection (figure (c)).
The bar magnet is now withdrawn from the coil, the galvanometer again gives a momentary deflection but in the opposite direction. So the electric current flows in opposite directin (figure (d)). Now if the magnet is moved faster, it gives a larger deflection due to a greater current in the circuit (figure (e)).
The bar magnet is reserved, i.e., the south pole now faces the coil. When the above experiment is repeated,the deflection are opposite to that obtained in the case of north pole (figure (f)).