$A$ completely filled water tank of height $h$ has a hole at the bottom. The total pressure at the bottom is $4H$ and the atmospheric pressure is $H$. The velocity of water flowing out of the hole is $(\rho = \text{density of water})$

$A$ cylindrical vessel of cross-section $A$ contains water to a height $h$. There is a hole in the bottom of radius $a$. The time in which it will be emptied is

$A$ cylinder of height $20\;m$ is completely filled with water. The velocity of efflux of water (in $m/s$) through a small hole on the side wall of the cylinder near its bottom is ....... $m/s$.

$A$ water tank of height $10\,m$,completely filled with water,is placed on a level ground. It has two holes,one at $3\,m$ and the other at $7\,m$ from its base. The water ejecting from:

$A$ cylindrical vessel of cross-sectional area $1000 \ cm^2$ is fitted with a frictionless piston of mass $10 \ kg$ and filled with water completely. $A$ small hole of cross-sectional area $10 \ mm^2$ is opened at a point $50 \ cm$ deep from the lower surface of the piston. The velocity of efflux from the hole will be ........... $m/s$.

$A$ large tank filled with water to a height $h$ is to be emptied through a small hole at the bottom. The ratio of times taken for the level of water to fall from $h$ to $h/2$ and from $h/2$ to $0$ is