Hair of shaving brush cling together when it is removed from water due to

A square wire frame of size $L$ is dipped in a liquid. On taking out, a membrane is formed. If the surface tension of liquid is $T,$ then force acting per unit length of the frame is

The work done in increasing the size of a soap film from $10 \mathrm{cm}\times 6 \mathrm{cm}$ to $10 \mathrm{cm}\times 11 \mathrm{cm}$ is $3\times {10}^{-4} \mathrm{J}$. The surface tension of the film is,

Two soap bubbles, each with a radius $r$, coalesce in vacuum under isothermal conditions to form a bigger bubble of radius $R$. Then $R$ is equal to

The excess pressure in a soap bubble of diameter $8\mathrm{cm}$ and surface tension $0.02 \mathrm{N} {\mathrm{m}}^{-1},$ is

A drop of water placed between two parallel glass plates which are then pressed together until the water film is $0.01 \mathrm{cm}$ Thick. If the area of water in contact with either plate is $10 {\mathrm{cm}}^2$, then the force due to surface tension drawing the plates together is (S.T. of water is $75 \mathrm{dyne} {\mathrm{cm}}^{-1}$)

The excess pressure inside a soap bubble is twice the excess pressure inside a second soap bubble. The volume of the first bubble is $n$ times the volume of the second; where $n$ is