(b) Describe one experiment to demonstrate the phenomenon of electromagnetic induction.

Solution:

(a) Whenever the number of magnetic field lines connected to a conductor changes, an electromotive force develops between the conductor’s ends. It lasts as long as the number of magnetic field lines changes. This phenomenon is Electromagnetic induction. This process of electromagnetic induction causes an electrical current.

(b) Demonstration of the electromagnetic induction phenomenon:

(i) When the magnet is stationary, the galvanometer has no deflection and the pointer reads zero, as shown in Figure 1. (a)

(ii) When the magnet is moved towards the solenoid with its north pole facing it, the galvanometer deflects to the right, indicating that current flows in the solenoid in the direction B to A, as illustrated in figure (b)

(iii) As the magnet’s motion comes to a halt, the pointer of the galvanometer returns to zero. This demonstrates that the current in a solenoid continues to flow as long as the magnet is moving.

(iv) When the magnet is pushed away from the solenoid, the galvanometer’s pointer moves to the left. The current in the solenoid flows again, but this time in the opposite direction as illustrated in the diagram (b)

(v) When the magnet is rapidly pushed away from the galvanometer. The deflection increases while the direction of deflection stays unchanged. It demonstrates that there are now more current flows.

(vi) The pointer of the galvanometer deflects to the left. This happens when the magnet is brought towards the solenoid by keeping its south pole towards it, as shown in figure (e). This demonstrates that the current in the solenoid flows in the opposite direction as illustrated in Figure 1. (b)