Question

A vertical capillary tube is brought in contact with the water surface (coefficient of surface tension T). The radius of the capillary is r and the angle of contact $0^{\circ }$ is . If $\rho$ is the density of water, the increase in the potential energy of the water due to capillary rise is

• A. $\frac{2\pi T^2}{\rho g}$
• B. $\frac{2\pi T^2}{\rho g}$
• C. $\frac{2T^2}{\rho g}$
• D. $\frac{2T^2}{g}$

Answer 1

The correct option is B

$\frac{2\pi T^2}{\rho g}$

$h=\frac{2T}{r\&g}$

Force due to surface tension, $F=\left(2\pi r\right)\left(T\right)$

Increase in potential Energy of water coloumn is equal to work done in displacing its centre of mass