Question

A square loop, carrying a steady current $I$, is placed in horizontal plane near a long straight conductor carrying a steady current $I_1$ at a distance $d$ from the conductor as shown in figure. The loop will experience

• A. a net repulsive force away from the conductor
• B. a net torque acting upward perpencicular to the horizontal plane
• C. a net torque acting downward normal to the horizontal plane
• D. a net attractive force towards the conductor

Answer 1

Answer: (D)

$F_2=-F_4$
$F_1=\frac{{\mu }_0{I}_{1}Il}{2\pi dl}$
$F_2=\frac{{\mu }_0{I}_{1}Il}{2\pi \left(d+l\right)}$
$F_1>F_3$
$F_{\text{net}}=F_1-F_3$
So, wire attract loop .