Figure shows the arrangment of two coils wound on a non-conducting cylindrical rod. The plugh of the key is then in¬serted and later removed.
(a) Deflection in the galvanometer remains zero throughout
(b) There is momentary deflection in the galvanometer that dies out shortly and deflections in both the cases are in the same direction
(c) There is momentary deflection in the galvanometer that dies out shortly and there is no effect when the key is re¬moved
(d) There are momentary deflections in both the cases that die out shortly but the deflections are in apposite directions.
Explanation : Due to electromagnetic induction, induced cur¬rent flows in the coil with which galvanometer is connected, when the key is inserted
(i.e. current grows in the primary coil) and when the key is removed (i.e. current decays in the primary coil).