Answer
$T=2\pi \sqrt{\frac{2R}{g}}$
Work Step by Step
We know that
$\omega=\sqrt{\frac{MgL}{I}}$
We also know that
$T=\frac{2\pi}{\omega}$
$\implies T=2\pi \sqrt{\frac{I}{MgL}}$
$Implies $ $
T=2\pi \sqrt{\frac{2MR^2}{MgR}}$
This simplifies to:
$T=2\pi \sqrt{\frac{2R}{g}}$
