There are two coils A and B as shown in the figure. A current starts flowing in B as shown when A is moved towards B and stops when A stops moving. The current in A is counterclockwise. B is kept stationary when A moves. We can infer that
(a) there is a constant current in the clockwise direction in A.
(b) there is a varying current in A.
(c) there is no current in A.
(d) there is a constant current in the counterclockwise direction in A.
The correct answer is the option (d)
Explanation:-
The problem infers that there is a constant current flowing in coil A, as when it is moved relative to coil B, the flux linked to B due to A is changed. This induces an emf in B, and hence current starts flowing. But when A is stopped there is no change in flux and hence no current would be induced in coil B. Whereas, if there were a changing current in coil A, then due to electromagnetic induction, there would have been an emf generated in B.