A boat carrying a number of stones is floating in a water tank. If the stones are unloaded into water, the water level in the tank will ............

A .......... $m/s$ speed the velocity head of water is equal to pressure head of $40\, cm$ of $Hg$ .

Two liquids having densities $d_1$ and $d_2$ are mixed in such a way that both have same mass. The density of the mixture is ............

A cylindrical vessel filled with water upto the height $H$ becomes empty in time $t_0$ due to a small hole at the bottom of the vessel. If water is filled to a height $4H$ it will flow out in time

If the terminal speed of a sphere of gold (density $= 19.5\, kg/m^3$ ) is $0.2\, m/s$ in a viscous liquid (density $= 1.5\, kg/m^3$ ), find the terminal speed of a sphere of silver (density $=10.5\, kg/m^3$ ) of the same size in the same liquid ........ $m/s$

A candle of diameter $d$ is floating on a liquid in a cylindrical container of diameter $D\left( {D >  > d} \right)$ as shown in figure. If it is burning at the rate of $2\  cm/hour$ then the top of the candle will