Question

A short bar magnet of magnetic moment $0.4J{T}^{-1}$ is place in a uniform magnetic field of $0.16T$. The magnet is stable equilibrium when the potential energy is

• A. $-0.064J$
• B. Zero
• C. $-0.082J$
• D. $0.064$

Answer 1

The correct option is A $-0.064J$

For stable equilibrium
$U=-MB$
$=-\left(0.4\right)\left(0.16\right)$
$=-0.064J$.