A $U$ tube contains water and methylated spirit separated by mercury . The mercury columns in the two arms are at the same level with $10\,cm$ of water in one arm and $12.5\,cm$ of spirit in the other as shown in figure. The relative density of the spirit is

A wooden block, with a coin placed on its top, floats in water as shown in fig. the distance $l$ and $h$ are shown there. After some time the coin falls into the water. Then

What is the pressure on a swimmer $20 \,m$ below the surface of water is ..... $atm$

There are two identical small holes of area of cross-section a on the opposite sides of a tank containing a liquid of density $\rho $. The difference in height between the holes is $h$. Tank is resting on a smooth horizontal surface. Horizontal force which will have to be applied on the tank to keep it in equilibrium is

Horizontal tube of non-uniform cross-section has radius of  $0.2\,m$ and  $0.1\,m$  respectively at $P$  and  $Q$ . For streamline flow of liquid, the rate of liquid flow

The rain drops are in spherical shape due to