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
.