• # 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

${{F}_{3}}\And {{F}_{4}}$cancel each other Force on PQ will be ${{F}_{1}}={{I}_{2}}{{B}_{1}}a$                                     $={{I}_{2}}\frac{{{\mu }_{0}}{{I}_{1}}}{2\pi a}a$                                     $=\frac{{{\mu }_{0}}{{I}_{1}}{{I}_{2}}}{2\pi }$ Force on RS will be ${{F}_{2}}={{I}_{2}}{{B}_{2}}a$                                     $={{I}_{2}}\frac{{{\mu }_{0}}{{I}_{1}}}{2\pi 2a}a$                                     $=\frac{{{\mu }_{0}}{{I}_{1}}{{I}_{2}}}{4\pi }$ Net force $={{F}_{1}}-{{F}_{2}}=\frac{{{\mu }_{0}}{{I}_{1}}{{I}_{2}}}{4\pi }$repulsion Option [b]