Water flows through a horizontal tube as shown in the figure. If the difference of heights of water column in the vertical tubes is $h=0.02 \mathrm{m}.$ And the areas of cross-section at $A$ and $B$ are $4\times {10}^{-4} {\mathrm{m}}^2$ and $2\times {10}^{-4} {\mathrm{m}}^2,$ Respectively, then the rate of flow of water across any section is

A cylindrical vessel contains a liquid of density $\rho$ up to a height $h$. The liquid is closed by a piston of mass $m$ and area of cross-section $A$. There is a small hole at the bottom of the vessel. The speed $v$ with which the liquid comes out of the hole is

In a cylindrical water tank there are two small holes $Q$ and $P$ on the wall at a depth of $h_1$ from the upper level of water and at a height of $h_2$ from the lower end of the tank, respectively, as shown in the figure. Water coming out from both the holes strike the ground at the same point. The ratio of $h_1$ and $h_2$ is

The velocity of the liquid coming out of a small hole of a large vessel containing two different liquids of densities $2\rho$ and $\rho$as shown in the figure is