Physics - Fluid Question with Solution | TestHub

The height of capillary rise is given by $h=\frac{2T\cos \theta }{\rho gr}$.

In a freely falling elevator, the effective acceleration due to gravity is $g_{eff}=g-g=0$.

Substituting $g_{eff}=0$ in the formula gives a theoretical height $h\to \infty$.

Since the liquid cannot rise beyond the length of the capillary tube, it rises to the top and the radius of curvature of the meniscus adjusts itself to prevent overflow.

Therefore, the water column will occupy the entire length of the capillary tube.

The length of the capillary tube is $20\text{cm}$, so the length of the water column will be $20\text{cm}$.

Answer: $20\text{cm}$