Two similar wires of equal lengths are bent in the form of a square and a circular loop. They are suspended in a uniform magnetic field and the same current is passed through them. The torque experienced by:

$A$ circular current loop of magnetic moment $M$ is in an arbitrary orientation in an external uniform magnetic field $\vec{B}$. The work done to rotate the loop by $30^{\circ}$ about an axis perpendicular to its plane is

$A$ uniform current-carrying ring of mass $m$ and radius $R$ is suspended by a massless string as shown. $A$ uniform magnetic field $B_0$ exists in the region to keep the ring in a horizontal position. Determine the current $I$ in the ring.

$A$ circular coil carrying a current of $2.5 \ A$ is free to rotate about an axis in its plane perpendicular to an external magnetic field. When the coil is made to oscillate, the time period of oscillation is $T$. If the current through the coil is $10 \ A$, the time period of oscillation is

$A$ disc of radius $r$ carrying a positive charge $q$ is rotating with an angular speed $\omega$ in a uniform magnetic field $B$ about a fixed axis as shown in the figure,such that the angle made by the axis of the disc with the magnetic field is $\theta$. The torque applied by the axis on the disc is:

The $(\tau - \theta)$ graph for a current-carrying coil in a magnetic field is: