Question

Two coils A and B of insulated wire are kept close to each other. Coil A is connected to a galvanometer while coil B is connected to a battery through a key. what would happed if :

(i) a current is passed through coil B by plugging the key ?

(ii) the current is stopped by removing the plug from the key ?

Explain your answer mentioning the name of the phenomenon involved.

Answer 1

(a)As the key is closed, the galvanometer needle will deflect for a moment and then return to zero.
(b)As the key is removed ,again a momentary deflection (but more) because of the change in magnetic flux linked with the coil is observed in the galvanometer in opposite direction .

The phenomenon involved is Electromagnetic induction.