Explain the effect of external magnetic field on current carrying loops. Describe torque on a current-carrying rectangular loop of wire on a pivot rod when placed in a magnetic field. Give alternative way of increasing the torque on the coil.

When a current-carrying loop is placed in an external magnetic field, the magnetic field exerts forces on the current-carrying sides of the loop. These forces do not necessarily cancel each other out as a net force, but they can produce a net torque that tends to rotate the loop. The loop behaves...