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 counterclockwise. `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 the counterclockwise direction in A

Answer

D

Explanation

Coil A must be carrying a constant current in counter clockwise direction. That is why when A moves towards B, current induced in B is in counter clockwise direction, as per Lenz's law. The current in B in would stop when A stops moving. Choice (d) is correct.