There is a small hole in hollow sphere. Water enters in sphere when it is taken at depth of $40\,cm$ in water. Diameter of hole is ....... $mm$ (Surface tension of water $= 0.07\, N/m$):

Two spherical soap bubbles formed in vacuum has diameter $3.0\,mm$ and $4.0\,mm$ . They coalesce to form a single spherical bubble. If the temperature remains unchanged, find the diameter of the bubble so formed ....... $mm$

There is an air bubble of radius $1.0\,mm$ in a liquid of surface tension $0.075\,Nm ^{-1}$ and density $1000\,kg$ $m ^{-3}$ at a depth of $10\,cm$ below the free surface. The amount by which the pressure inside the bubble is greater than the atmospheric pressure is $....Pa \left( g =10\,ms ^{-2}\right)$

Excess pressure of one soap bubble is four times more than the other. Then the ratio of volume of first bubble to another one is

The surface tension and vapour pressure of water at $20^{°}$ $\mathrm{C}$ is $7.28 \times {10^{ - 2}}\,{\rm{N/m}}$ and $2.33 \times {10^3}\,{{\rm{P}}_{\rm{a}}}$ respectively. What is the radius of the smallest spherical water droplet which can form without evaporating at $20^{°}$ $\mathrm{C}$ ?

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