my ques

As the bar is lowered in the vessel of smaller cross section, water will spill into the outer vessel.

Ignoring the volume of the fluid coming out of the orifice, the level of fluid in the outer vessel as a function of time is H*=(H) (H/8)(v)(t)/(2A).

And for the velocity through the orifice, efflux formula: √2g.H*...

Ans=\sqrt{H^{2}gtv/8A}