Q 12-05-036JEE MainJEE Main 2023 (31 Jan, Shift 1)Easy
A bar magnet with a magnetic moment $5.0\ \text{A m}^2$ is placed in parallel position relative to a magnetic field of $0.4\ \text{T}$. The amount of required work done in turning the magnet from parallel to antiparallel position relative to the field direction is ______.
Answer: (A) $4\ \text{J}$
$W=mB(\cos0^\circ-\cos180^\circ)=2mB=2\times5\times0.4=4\ \text{J}$.
Solution by Sreeraj P, M.Sc Physics