Question

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 of $A$
• 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 1

Answer: (D)

Coil A must be carrying a constant current in counter clockwise direction. Because of that, when $A$ moves towards $B$, current induced in $B$ is counterclockwise direction as per Lenz’s law. The current in $B$ would stop when $A$ stops moving.