A simple pendulum of length $l$ Has maximum angular displacement $\theta$. The maximum kinetic energy of the bob of mass $m$ is $\left(g= \mathrm{acceleration} \mathrm{due} \mathrm{to} \mathrm{gr}a\mathrm{vity}\right)$

A simple pendulum with a bob of mass ' $m^{\text{'}}$ oscillates from $A$ to $C$ and back to $A$ such that $PB$ is $H$. If the acceleration due to gravity is '$g$', then the velocity of the bob, as it passes through $B$ is