A small circular coil of 20 turns of wire lies in a uniform field of 0.5 T, so that the normal to the plane of the coil makes an angle of 60 degrees with the direction B (magnetic field with arrow over top). The radius of the coil is 4 cm, and it carries a current of 3 A. (a) what is the magnitude of the magnetic moment of the coil? (b) what is the magnitude of the torque exerted on the coil?
The magnetic dipole moment of a coil is m = N?I?A, where N=20 is the number of turns, I = 3 A is the current, and A = pi?r^2 = 16pi cm^2 = 0.0016pi m^2 is the area of the coil, ...
The solution examines the magnitude of the magnetic moment of the coil. The magnitude of the torque exerted on the coil is found.