A current of 16.5 mA is maintained in a single circular loop with a circumference of 2.55 m. A magnetic field of 0.720 T is directed parallel to the plane of the loop. What is the magnitude of the torque exerted by the magnetic field on the loop?

0.0062 Nm

Explanation:

Parameters given:

Number of turns, N = 1

Current, I = 16.5 mA = 0.0165 A

Circumference of loop = 2.55 m

Magnetic field strength, B = 0.720 T

The torque exerted by a magnetic field is given as:

τ = N * I * A * B * sinθ

θ = angle between the perpendicular of the loop to the magnetic field (90° in this case)

Where A = area of loop.

First we find the radius of the loop:

Circumference = 2.55 = 2 * pi * r

=> r = 2.55 / (2 * 3.142)

r = 0.406

Area = pi * r²

Area = 3.142 * 0.406²

Area = 0.52 m²

Therefore, torque is:

τ = 1 * 0.0165 * 0.52 * 0.72 * sin90

τ = 0.0062 Nm