If the rise in heights of capillary of two tubes are $6.6\,cm$ and $2.2\,cm$,then the ratio of the radii of the tubes is

$A$ capillary tube is taken from the Earth's surface to the Moon's surface. What happens to the rise of the liquid column on the Moon's surface? (Acceleration due to gravity on the Earth's surface is six times that of the Moon's surface.)

$A$ vertical glass capillary tube open at both ends contains some water. Which of the following shapes may be taken by the water in the tube?

Two vertical parallel plates are partially submerged in water. The distance between the plates is equal to $d$. Water rises due to surface tension $T$,the width of the plates is $l$,and the contact angle of water with glass is $0^o$. Find the force of attraction between the plates.

Why does the mercury level fall in a capillary tube? Explain.

$A$ capillary tube of radius '$r$' is immersed in water and water rises to a height of '$h$'. The mass of water in the capillary tube is $5 \times 10^{-3} \ kg$. The same capillary tube is now immersed in a liquid whose surface tension is $\sqrt{2}$ times the surface tension of water. The angle of contact between the capillary tube and this liquid is $45^{\circ}$. The mass of liquid which rises into the capillary tube now is (in $kg$):