Q 11-09-145JEE MainJEE Main 2019 (9 Apr, Shift 1)Easy
If $M$ is the mass of water that rises in a capillary tube of radius $r$, then mass of water which will rise in a capillary tube of radius $2r$ is
Answer: (B) $2M$
Capillary rise $h = \dfrac{2T\cos\theta}{r\rho g}$, so the mass raised is
$$m = \pi r^2h\rho = \frac{2\pi rT\cos\theta}{g} \propto r$$
Doubling the radius doubles the mass: $2M$.
Solution by Sreeraj P, M.Sc Physics