question_answer

A rigid square loop of side 'a' and carrying current \[{{I}_{2}}\]is lying on a horizontal surface near a long current \[{{I}_{1}}\]carrying wire in the same plane as shown in figure. The net force on the loop due to wire will be : [JEE Main 9-4-2019 Morning]

A) Attractive and equal to \[\frac{{{\mu }_{0}}{{I}_{1}}{{I}_{2}}}{3\pi }\]

B) Repulsive and equal to \[\frac{{{\mu }_{0}}{{I}_{1}}{{I}_{2}}}{4\pi }\]

C) Repulsive and equal to\[\frac{{{\mu }_{0}}{{I}_{1}}{{I}_{2}}}{2\pi }\]

D) Zero

Correct Answer: B

Solution :

[b]

cancel each other

Force on PQ will be

Force on RS will be

Net force repulsion

Option [b]