Question

A short bar magnet placed with its axis at 30º with a uniform external magnetic field of 0.25 T experiences a torque of magnitude equal to 4.5 × 10⁻² J. What is the magnitude of magnetic moment of the magnet?

Answer 1

Magnetic field strength, B = 0.25 T

Torque on the bar magnet, T = 4.5 × 10⁻² J

Angle between the bar magnet and the external magnetic field,θ = 30°

Torque is related to magnetic moment (M) as:

T = MB sin θ

Hence, the magnetic moment of the magnet is 0.36 J T⁻¹_.