Question

A rectangular loop carrying a current ` i` is situated near a long straight wire such that the wire is parallel to one of the sides of the loop and is in the plane of the loop . If steady current ` I` is established in the wire as shown in the figure ,

A. rotate about an axis parallel to the wire
B. move away form the wire
C. move toward the wire
D. remain stationary

Answer 1

Correct Answer - c
is the correct option. Part AB of the rectangular loop will get attracted to the long straight wire as the currents are parallel and in the same direction whereas part CD will be repelled. But since this force `Fprop(1//r)` where r is the distance between the wires.
Therefore, there will be a net attractive force on the rectangular loop.