Question

A capillary tube of radius R is immersed in water and water rises in it to a height H. Mass of water in the capillary tube is M, If the radius of the tube is doubled mass of water that will rise in capillary tube water be

• A. 2M
• B. M
• C. $\frac{M}{2}$
• D. 4M

Answer 1

The correct option is A 2M

Mass of water in capillary rise $=Ah\rho$

$A=$ area of cross-section, $h=$ height, $\rho =$ density

$\Rightarrow m=\left(\pi r^2\right)h\rho =\pi r^2\times \frac{2\sigma \cos \theta }{r\rho g}$

$\Rightarrow m\propto r$

$\therefore$ Doubling radius $\Rightarrow$mass will also get doubled

$m^{\prime }=2M$