AAI ATC Junior Executive 25 Mar 2021 Shift 2 Paper

A circular coil of 50 turns and a radius of 10 cm carrying a current of 5.0 A is suspended vertically in a uniform horizontal magnetic field of magnitude 1.0 T. The field lines make an angle of 90° with the normal of the coil. Calculate the magnitude of the counter torque that must be applied to prevent the coil from turning?