A short bar magnet of magnetic moment 0.8 JT-1 is placed in a uniform magnetic field of 0.32 T . The magnet is in stable equilibrium. When the potential energy is

Here magnetic moment  M=0.8 JT−1Magnetic field  B=0.32 TWhen a bar magnet is placed in a uniform magnetic field; its potential energy U=-M→. B→ ⇒U=-MBcosθFor stable equilibrium  θ=0⇒U=-MB ⇒U=-0.8×0.32 ⇒U=-0.256 J .