Find torque on the loop.

Question

Given figure shows a coil bent with all edges 1 m and carrying a current of 1 A. There exists in space a uniform magnetic field of 2 T in positive y-direction. Find the torque on the loop.

Answer 1

The forces on the edges FG and BC are zero. The forces on the other edges are:

The torque of the forces FAB and FHG is zero and that of FCD and FEF is zero.

The forces on the edges AH and DE are equal and opposite and so constitutes a net torque. Thus