Question

(a) A coil of insulated wire is connected to a galvanometer. What would be seen if a bar magnet with its south pole towards one face of the coil is
(i) moved quickly toward it

(ii) moved quickly away from it

(iii)placed near its one face.

These activities are then repeated with north pole of the magnet. What will be the observations?

(b) Name and define the phenomenon involved in above activities.

(c) Name the rule which can determine the direction of current in each case.

Answer 1

(a) A coil of insulated wire is connected to a galvanometer and if a bar magnet with its south pole, towards one face of the coil, is
(i) moved quickly towards it, the galvanometer is deflected towards the left.

(ii) When magnet is moved quickly away from the coil, the galvanometer is deflected towards the right.

(iii) If the magnet is held stationary inside the coil, the deflection of the galvanometer is zero. If this activity is repeated with north pole of the magnet :

(i) If the magnet is pushed into the coil, the galvanometer is deflected towards the right.

(ii) If the magnet is withdrawn from the coil, the galvanometer is deflected towards the left.

(iii)If the magnet is held stationary inside the coil, the deflection of the galvanometer is zero.
(b) The phenomenon involved in this activity is 'Electromagnetic Induction'. The production of electric current by moving a magnet near a fixed coil of wire is called electromagnetic induction.

(c) The direction of induced current is determined by 'Fleming's Right Hand Rule'.