A short bar magnet of magnet moment `0.4 JT^(-1)` is placed in a uniform magnetic field of 0.16 T. The magnet is in stable equilibrium when the potential energy is :

Options

A. `-0.064 J`
B. zero
C. `-0.082 J`
D. 0.064 J

Answer

A

Explanation

For state equilibrium
`U=-MB`
`=-(0.4) (0.16)`
`=-0.064 J`