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

A drop of water of volume $0.05\, cm^3$ is pressed between two glass plates, as a consequence of which it spreads and occupies an area of $40\, cm^2$. If the surface tension of water is $70\, dyne/cm$, then the normal force required to separate out the two glass plates will be in Newton

The diameter of rain-drop is $0.02 \,cm$. If surface tension of water be $72 \times {10^{ - 3}}\,newton$ per metre, then the pressure difference of external and internal surfaces of the drop will be

When two soap bubbles of radii $a$ and $b ( b > a )$ coalesce, the radius of curvature of common surface is

The excess pressure inside a soap bubble is thrice the excess pressure inside a second soap bubble. The ratio between the volume of the first and the second bubble is:

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