A wide vessel of uniform cross-section with a small hole in the bottom is filled with thick layer of water and
thick layer of kerosene. The relative density of kerosene is 0.8 . The inital velocity of flow of water streaming out of the hole is
Let and
be the densities of water and kerosene. The initial weight of the liquid in the vessel
where
and
are the thicknesses of water and kerosene layers and a is the cross-sectional area of the vessel. Let this weight be equivalent to water layer of thickness h, then
or
From Torricelli's theorem, the velocity of efflux is
Hence the correct choice is (d).