The value of Potential energy in stable equilibrium of a dipole moment 'm' in an uniform magnetic field B is ​

Question

The value of Potential energy in stable equilibrium of a dipole moment 'm' in an uniform magnetic field \(\overrightarrow{B}\) is

(A) mB

(B) -mB

(C) 2mB

(D) - 2mB

Answer 1

Correct option is: (B) -mB

Potential energy \(U_m = \vec m.\vec B =mB\cos \theta\)

At \(\theta = 0^\circ\) the dipole will be in most stable position

\(U_m = -mB\cos \theta \)

\(= -mB\cos 0^\circ\)

\(= - mB\)

Answer 2

Correct option is: (B) -mB