$A$ capillary tube of radius $0.1 \,mm$ is dipped in water. The water rises to a height of $2 \,cm$ in the tube. If the surface tension of water is $0.072 \,N/m$, the contact angle between water and the wall of the tube is:

The kerosene oil rises up in the wick of a lamp ...........

Liquid $A$ rises to a height of $10 \ cm$ in a capillary tube and liquid $B$ falls to a depth of $2 \ cm$ in the same tube. The densities of $A$ and $B$ are $1 \ g/cm^3$ and $10 \ g/cm^3$ respectively. The contact angles of $A$ and $B$ with the tube are $0^{\circ}$ and $135^{\circ}$ respectively. If the surface tensions of $A$ and $B$ are $S_A$ and $S_B$, then the ratio $\frac{S_B}{S_A}$ is:

The following observations were taken for determining surface tension $T$ of water by the capillary method:
Diameter of capillary,$D = 1.25 \times 10^{-2} \; m$
Rise of water,$h = 1.45 \times 10^{-2} \; m$
Using $g = 9.80 \; m/s^2$ and the simplified relation $T = \frac{rhg}{2} \times 10^3 \; N/m$,the possible error in surface tension is ........... $\%$. (Assume the least count of the measuring instrument is $0.01 \times 10^{-2} \; m$)

Two capillaries made of the same material but of different radii are dipped in a liquid. The rise of liquid in one capillary is $2.2 \ cm$ and that in the other is $6.6 \ cm$. The ratio of their radii is

$A$ capillary tube,when immersed vertically in a liquid,records a rise of $3 \, cm$. If the tube is immersed in the liquid at an angle of ${60^\circ}$ with the vertical,what is the length of the liquid column along the tube in $cm$?