Q ​Time period of a simple pendulum is T and its angular amplitude is ${\theta }_0$. Find time taken by the bob to move from equilibrium position O to P if at this instant string makes an angle $\theta$ with the vertical. 
$$\begin{gathered} 1. \frac{T}{\mathrm{\pi }}{\sin }^{-1}\left(\frac{\theta }{{\theta }_0}\right) \\ 2.\frac{T}{2\mathrm{\pi }}{\sin }^{-1}\left(\frac{\theta }{{\theta }_0}\right) \\ 3. T{\sin }^{-1}\left(\frac{{\theta }_0}{\theta }\right) \\ 4. T{\sin }^{-1}\left(\frac{\theta }{{\theta }_0}\right) \end{gathered}$$