Q 11-09-009NEETNEET 2020Top questionMedium
A capillary tube of radius r is immersed in water and water rises in it to a height h. The mass of the water in the capillary is $5$ g. Another capillary tube of radius $2$r is immersed in water. The mass of water that will rise in this tube is :
Answer: (C) $10.0$ g
Capillary rise: $h = \dfrac{2S\cos\theta}{r\rho g}$, so $h \propto \dfrac{1}{r}$.
Mass of the raised column: $m = \pi r^2h\rho \propto r^2 \cdot \dfrac{1}{r} = r$.
Doubling the radius doubles the mass: $2 \times 5 = 10$ g.
Solution by Sreeraj P, M.Sc Physics