
Here $I=\frac{m l^{2}}{3}+\frac{m l^{2}}{3}=\frac{2 m g l^{2}}{3}$
From figure: $\sin 45^{\circ}=\frac{L}{l / 2}$
$\therefore \mathrm{L}=\frac{l}{2 \sqrt{2}}$
$\therefore \quad \mathrm{T}=2 \pi \sqrt{\frac{2 \mathrm{m} l^{2}}{3 \times \frac{l}{2 \sqrt{2}} \mathrm{mg}}}=2 \pi \sqrt{\frac{2 \sqrt{2} l}{3 \mathrm{g}}}$




