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 happen 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

(i) If current is passed through coil B by plugging key, the galvanometer pointer will move to one side. The movement of galvanometer pointer shows that a current is induced in the coil.
(ii) In this case, galvanometer pointer moves to other side. This shows that the direction of induced current is reversed and then quickly returned to zero.
This phenomenon is based on the principle of electromagnetic induction.