A circular coil of radius r = 10 ,cm having 300 turns carries a current of 2A. The coil is suspended vertically in a uniform magnetic field of strength 0.7 T. If the plane of the coil makes an angle 30^ with the magnetic field, the torque needed to prevent it from turning is:

Step-by-step solution

Given: Number of turns, N = 300 Current, I = 2 A Radius, r = 10 cm = 0.1 m Magnetic field, B = 0.7 T The angle between the plane of the coil and the magnetic field is 30^ . The angle between the area vector (normal to the plane) and the magnetic field is = 90^ - 30^ = 60^ . Area of the coil, A = r^2 = (0.1)^2 = 0.01 m ^2 The torque experienced by the coil is given by: = N I A B Substituting the values: = 300 2 0.01 0.7 60^ = 6 0.7 3 2 = 2.1 3 Using 3.14 and 3 1.732 : 2.1 3.14 1.732 11.42 Nm The torque needed to pre