Q 11-09-025NEETJEE MainMedium
In a capillary tube water would rise to $6$ cm, but the tube sticks out only $4$ cm above the water surface. Then
Answer: (C) water rises to the top and stops, with a meniscus of larger radius
$hR = \dfrac{2T}{\rho g}$ is fixed, where $R$ is the radius of curvature of the meniscus. With $h$ limited to $4$ cm, the meniscus flattens so that its radius grows to $\dfrac{6}{4}$ of its usual value. The water does not overflow, because nothing supplies the energy for a continuous flow.
Solution by Sreeraj P, M.Sc Physics