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 cosntant 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 counerclock-wise direction in `A`.

Answer

D

Explanation

When the `A` stops moving the current in `B` become zero, it possible only if the current in `A` is constant. If the current in `A` would be variable, there must be an included emf (current) in `B` even if `A` stops moving.