Physics - Magnetism Question with Solution | TestHub

A bar magnet of magnetic moment $M$ is placed in a uniform magnetic field $B$.

Maximum torque on the magnet:

${\tau }_{\max }=MB$

If the torque is reduced to half of maximum:

$\tau =\frac{1}{2}{\tau }_{\max }$

Torque on a magnetic dipole:

$\tau =MB\sin \theta$

Setting $\tau =\frac{1}{2}{\tau }_{\max }$:

$MB\sin \theta =\frac{1}{2}MB$

$\sin \theta =\frac{1}{2}$

$\theta =30^{\circ }$