# A circular disc of radius 0.2 m is placed in a uniform magnetic field of inducion $\large\frac{1}{\pi} \bigg( \large\frac{ \omega b}{m^2} \bigg)$ in such a way that its axis makes an angle of $60^{\circ}$ with $\overrightarrow B$. The magnetic flux linked with the disc is :

$\begin {array} {1 1} (1)\;0.01\: \omega\: b & \quad (2)\;0.02\: \omega\: b \\ (3)\;0.06\: \omega\: b & \quad (4)\;0.08\: \omega\: b \end {array}$