Question

Two identical circular loops of metal wire are lying on a table without touching each other. Loop A carries a current which increases with time. In response, the loop B

• A. remains stationary
• B. is attracted by the loop A
• C. is repelled by the loop A
• D. rotates about its CM, with CM fixed

Answer 1

Answer: (C)

is repelled by the loop A

Answer 2

For understanding, let us assume that the two loops are lying
in the plane of paper as shown. The current in loop 1 will
produce $\odot$ magnetic field in loop 2. Therefore, increase in
current in loop 1 will produce an induced current in loop 2
which produces $\otimes$ magnetic field passing through it i.e.
induced current in loop 2 will also be clockwise as shown in
the figure.
The loops will now repel each other as the currents at the
nearest and farthest points of the two loops flow in opposite
directions.