The force required to separate two glass plates of area $10^{-2} \, m^2$ with a film of water $0.05 \, mm$ thick between them is ...... $N$. (Surface tension of water is $70 \times 10^{-3} \, N/m$)

The excess of pressure,due to surface tension,on a spherical liquid drop of radius $R$ is proportional to

Under isothermal conditions,two soap bubbles of radii $r_{1}$ and $r_{2}$ coalesce to form a single larger bubble. The radius of the larger bubble is

$A$ spherical soap bubble inside an air chamber at pressure $P_0 = 10^5 \ Pa$ has a certain radius $R$ such that the excess pressure inside the bubble is $\Delta P = 144 \ Pa$. Now,the chamber pressure is reduced to $8P_0 / 27$ so that the bubble radius and its excess pressure change. In this process,all temperatures remain unchanged. Assume air to be an ideal gas and the excess pressure $\Delta P$ in both cases to be much smaller than the chamber pressure. The new excess pressure $\Delta P'$ in $Pa$ is:

If two soap bubbles of different radii are connected by a tube,

Two soap bubbles of radii $3r$ and $4r$ are in contact with each other. The radius of curvature of the interface between the bubbles is: