A capillary tube of radius $r$ is dipped in a liquid of density $\rho$ and surface tension $S$. If the angle of contact is $\theta$, the pressure difference between the two surfaces in the beaker and the capillary

The adjoining diagram shows three soap bubbles $A, B$ and $C$ prepared by blowing the capillary tube fitted with stop cocks, $S_1$, $S_2$ and $S_3$. With stop cock $S$ closed and stop cocks $S_1$, $S_2$ and $S_3$ opened

Two soap bubbles of radii $2 \,cm$ and $4 \,cm$ join to form a double bubble in air, then radius of curvature of interface is .......... $cm$

If pressure at half the depth of a lake is equal to $2/3$ pressure at the bottom of the lake then what is the depth of the lake...... $m$

If a section of soap bubble (of radius $R$) through its center is considered, then force on one half due to surface tension is

A liquid column of height $0.04 \mathrm{~cm}$ balances excess pressure of soap bubble of certain radius. If density of liquid is $8 \times 10^3 \mathrm{~kg} \mathrm{~m}^{-3}$ and surface tension of soap solution is $0.28 \mathrm{Nm}^{-1}$, then diameter of the soap bubble is . . . . . . .. . $\mathrm{cm}$.

$\text { (if } g=10 \mathrm{~ms}^{-2} \text { ) }$