Question

A student connects a coil of insulated wire to a galvanometer. What would be seen if a bar magnet with its north pole towards one face of the coil is:
(a) moved quickly towards it?
(b) moved quickly away from the coil?
(c) placed near the face of the coil?
​Name the phenomenon involved.

Answer 1

(a) When the bar magnet is moved quickly towards the coil, a deflection is observed in the galvanometer. This deflection indicates that some current is produced in the coil.

(b) When we move the magnet quickly away from the coil, this time the deflection is indicated in the opposite direction. It indicates the current produced in the coil is in the opposite direction.

(c) When we simply move the magnet near the face of the coil then no deflection is found in the galvanometer, because of the absence of relative motion between the coil and the magnet.

The phenomenon involved is known as Electromagnetic induction.