There are two coils A and B as shown in 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 counter clockwise. B is kept stationary when A moves. We can infer that

Options

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 counterclockwise direction in A.

Answer

D

Explanation

When A is moved towards B, current starts flowing in B and when A stops, the current also stops it means there is a constant current flows in loop A. If variable current is flowing in loop A than it can produce current in loop B in stationary state as well.
Now induced current in loop B is in counter clockwise which indicates that in loop A also current should be in counter clockwise according to Lenz.s law. (Consider loop A as magnet and think about how magnetic field lines of loop A link with loop B).