$A$ $20 cm$ long capillary tube is dipped vertically in water and the liquid rises up to $10 cm$. If the entire system is kept in a freely falling platform, the length of the water column in the tube will be (in $cm$)

Water rises to a height of $10 \ cm$ in a certain capillary tube. Another identical tube when dipped in mercury,the level of mercury is depressed by $3.42 \ cm$. The density of mercury is $13.6 \ g/cc$. The angle of contact for water in contact with glass is $0^o$ and for mercury in contact with glass is $135^o$. The ratio of the surface tension of water to that of $Hg$ is:

$A$ glass capillary of radius $0.35 \ mm$ is inclined at $60^{\circ}$ with the vertical in water. The length of the water column in the capillary is (surface tension of water $= 7 \times 10^{-2} \ N/m$,acceleration due to gravity $g = 10 \ m/s^2$,$\cos 0^{\circ} = 1$,$\cos 60^{\circ} = 0.5$,density of water $\rho = 10^3 \ kg/m^3$) (in $cm$)

It is not possible to write directly on blotting paper or newspaper with an ink pen.

$A$ $U$-tube with limbs of diameters $5\, mm$ and $2\, mm$ contains water of surface tension $7 \times 10^{-2} \, N/m$. The angle of contact is zero and the density of water is $10^3 \, kg/m^3$. If $g = 10 \, m/s^2$,then the difference in the liquid levels of the two limbs is:

$A$ capillary tube of radius $r$ is immersed in a liquid and the mass of the liquid which rises up in it is $M$. If the radius of the tube is doubled,then the mass of the liquid which will rise in the capillary tube will be ............