A coil of single turn is wrapped around a sphere of radius ' \( r \...

A coil of single turn is wrapped around a sphere of radius ' \( r \) ' and mass ' \( m \) '. The plane of the coil is parallel to the inclined plane and lies in the equatorial plane of the sphere. If the sphere is in rotational equilibrium, the value of strength of uniform magnetic field in vertically downward direction is : (current in the coil is \( \mathrm{I} \) as shown in figure)
(1) \( \frac{\mathrm{mg}}{\pi \mathrm{lr}} \)
(2) \( \frac{\mathrm{mg}}{\pi \operatorname{lr} \sin \theta} \)
(2) \( \frac{m g \sin \theta}{\pi \mathrm{lr}} \)
(3) None of these