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

$A$ vertical capillary tube is filled with water up to the top after closing its lower end with a finger. If the finger is removed,we shall observe that: ($T = 70 \,\, dyne/cm$,radius of capillary $r = 1 \,\, mm$ and $g = 980 \,\, cm/sec^2$)

Two capillary tubes $A$ and $B$ of the same internal diameter are kept vertically in two different liquids whose densities are in the ratio $4:3$. If the surface tensions of these two liquids are in the ratio $6:5$,then the ratio of rise of liquid in capillary $A$ to that in $B$ is (assume their angles of contact are nearly equal).

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.

$A$ glass capillary tube of inner diameter $0.28 \,mm$ is lowered vertically into water in a vessel. The pressure to be applied on the water in the capillary tube so that the water level in the tube is the same as that in the vessel is ............ $\times 10^3 \,N/m^2$ (surface tension of water $= 0.07 \,N/m$ and atmospheric pressure $= 10^5 \,N/m^2$).

$A$ 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.)