$A$ straw of circular cross-section of radius $R$ and negligible thickness is dipped vertically into a liquid of surface tension $T$. If the contact angle between the liquid and the straw material is $53^{\circ}$,what is the force acting on the straw due to the surface tension of the liquid? (Given: $\cos 53^{\circ} = 0.6$)

$A$ metal sheet $4 \ m$ on a side and of negligible thickness is attached to a balance and inserted into a container of fluid. The balance to which the metal sheet is attached reads $0.50 \ N$ and the contact angle is found to be $0^{\circ}$. $A$ small amount of oil is then spread over the metal sheet. The contact angle now becomes $180^{\circ}$ and the balance now reads $0.49 \ N$. The surface tension of the fluid is:

Water is filled up to a height $h$ in a beaker of radius $R$ as shown in the figure. The density of water is $\rho$,the surface tension of water is $T$ and the atmospheric pressure is $P_0$. Consider a vertical section $ABCD$ of the water column through a diameter of the beaker. The force on water on one side of this section by water on the other side of this section has magnitude

It is easy to wash clothes in hot water because its

Consider a bowl filled with water on which some black pepper powder has been sprinkled uniformly. Now,a drop of liquid soap is added at the centre of the surface of water. The picture of the surface immediately after this will look like:

$A$ pin or a needle floats on the surface of water,the reason for this is: