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 ,

Options

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

Answer

C

Explanation

`AB` part of the rectangular loop will get attracted to the long straight wire as the currents are parallel and in the same direction whereas ` CD` part will be repelled . But since this force `F prop (1)/( r)` where ` r` is the distance between the wires . Therefore, there will be a net attractive force on the rectangular loop. Force on ` BC` is equal and opposite to that on `AD`.