The plane of a 5.0 cm × 8.0 cm rectangular loop of wire is parallel to a 0.19 T magnetic field. The loop carries a current of 6.2 A.<br> (a)What torque acts on a loop?<br>(b) What is the magnetic moment of the loop? <br>(c)What is the maximum torque that can be obtained with the same total length wire carrying the same current in this magnetic field?

Solution:

Given:

Magnetic Field (B) = 0.19T

Current (I) = 6.2A

Rectangle dimensions = 5cm × 8cm = 0.05m × 0.08m

Thus,

Area; A = 0.05m × 0.08m = 0.004 m²

And,

Torque (τ) = BIA

τ = 0.19 × 6.2 × 0.004

τ = 4.712 × 10^-3 J

a) Thus, the torque acting on loop is 4.712 × 10^-3 J.

Again,

Magnetic Moment (M) = IA

M = 6.2 × 0.004

M = 0.0248 J/T

b) Thus, Magnetic moment of the loop is 0.0248 J/T