Q. A short bar magnet of magnetic moment $0.4\ J\ T^{- 1}$ is placed in a uniform magnetic field of $0.16\ T$. The magnet is in stable equilibrium when the potential energy is
A) $- 0.082\ J$
B) 0.064 $J$
C) $- 0.064\ J$
D) Zero
Explanation
(c) For stable equilibrium
$U = - MB$
$= - (0.4)(0.16) = - 0.064\ J$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.