2. 

A simple pendulum with bob of mass m and conducting wire of length L swings under gravity through an angle $2\theta$. The earth's magnetic field component in the direction perpendicular to swing is B. The maximum potential difference induced across the pendulum is

$$\begin{gathered} \left(1\right) 2BL \sin \left(\frac{\theta }{2}\right).\sqrt{gL} \left(2\right) BL \sin \left(\frac{\theta }{2}\right)\sqrt{gL} \\ \left(3\right) BL \sin \left(\frac{\theta }{2}\right). (gL{)}^{3/2} (4) BL \sin \left(\frac{\theta }{2}\right). (gL{)}^2 \end{gathered}$$