A circular coil of wire of 200 turns and diameter 6 cm carries a current of 7 A.It is placed in a magnetic field of 0.90 T with the plane of the coil making an angle of 30° with the magnetic field.What is the torque on the coil?
A)3.1 N ∙ m
B)1.8 N ∙ m
C)5.9 N ∙ m
D)8.2 N ∙ m
E)1.5 N ∙ m

Question

Quizplus · Accepted Answer

The torque on a coil is given by τ = n * I * A * B * sin(θ), where n is the number of turns, I is the current, A is the area of the coil, B is the magnetic field, and θ is the angle between the normal to the coil and the magnetic field. Here, n = 200, I = 7 A, B = 0.90 T, θ = 30°, and the area A = π * (0.03 m)^2. Calculating this gives τ = 3.1 N ∙ m.

A Circular Coil of Wire of 200 Turns and Diameter