Question

Two identical conductors $P$ and $Q$ are placed on two frictionless, flat, conducting rails $R$ and $S$, in a uniform magnetic field directed into the plane. If conductor $P$ is moved in the direction shown in the figure with a constant speed, then the conductor $Q$ -

• A. will be attracted towards conductor $P$
• B. will be repelled away from conductor $P$
• C. will remain stationary
• D. first attracted and then repelled away from conductor $P$

Answer 1

The correct option is A will be attracted towards conductor $P$


As the conductor $P$ moves away from conductor $Q,$ the area of the loop, enclosed by the conductors and the rails, increases.

This, in turn, increases the flux through the loop.

EMF will be induced in such a way that the change in flux will be resisted.

The induced current will cause conductor $Q$ to move towards conductor $P$, thereby, reducing the area, and thus the flux.

Therefore, conductor $Q$ will be attracted towards conductor $P$.

Hence, option $\left(A\right)$ is the correct answer.