$A$ soap bubble is in the form of a circular tube having a radius of curvature $R$ and a radius of curvature perpendicular to it of $5R$. Find the excess pressure in the bubble.

If the excess pressure inside a soap bubble is balanced by an oil column of height $2\, mm$,then the surface tension of the soap solution will be $(r = 1\, cm$ and density $d = 0.8\, g/cm^3)$.

Pressure inside two soap bubbles are $1.02 \ atm$ and $1.05 \ atm$ respectively. The ratio of their surface area is

If two glass plates have water between them and are separated by a very small distance (see figure),it is very difficult to pull them apart. This is because the water in between forms a cylindrical surface on the side that gives rise to a lower pressure in the water in comparison to the atmosphere. If the radius of the cylindrical surface is $R$ and the surface tension of water is $T$,then the pressure in the water between the plates is lower by:

$A$ soap bubble (surface tension $= T$) is charged to a maximum surface density of charge $= \sigma$. When it is just about to burst,its radius $R$ is given by:

$A$ spherical drop of oil of radius $1\, cm$ is broken into $1000$ droplets of equal radii. If the surface tension of oil is $50\, dynes/cm$,the work done is