The excess pressure due to surface tension in a spherical liquid drop of radius r is directly proportional to

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

A soap bubble is blown with the help of a mechanical pump at the mouth of a tube. The pump produces a certain increase per minute in the volume of the bubble, irrespective of its internal pressure. The graph between the pressure inside the soap bubble and time $t$ will be-

A small soap bubble of radius $4\,cm$  is trapped inside another bubble of radius $6\,cm$ without any contact. Let $P_2$  be the pressure inside the inner bubble and $P_0$  the pressure outside the outer bubble. Radius of another bubble with pressure difference $P_2 - P_0$  between its inside and outside would be....... $cm$

A vertical glass capillary tube of radius $r$ open at both ends contains some water (surface tension $T$ and density $\rho$ ). If $L$ be the length of the water column, then:

The volume of an air bubble becomes three times as it rises from the bottom of a lake to its surface. Assuming atmospheric pressure to be $75\, cm$ of $Hg$ and the density of water to be $1/10  $ of the density of mercury, the depth of the lake is ....... $m$