A magnetic dipole experiences a torque of 80√3 N·m in a uniform magnetic field when its dipole moment makes an angle 60° with the field. The potential energy of the dipole is:
Options

Question

A magnetic dipole experiences a torque of 80√3 N·m in a uniform magnetic field when its dipole moment makes an angle 60° with the field. The potential energy of the dipole is:

G1 Physics · Accepted Answer

Torque on a magnetic dipole is τ = MB sinθ. Given, τ = 80√3 N·m, θ = 60°. Therefore, 80√3 = MB(√3/2) ⇒ MB = 160 J. Potential energy is U = -MB cosθ = -160(1/2) = -80 J. Correct option: D.