A spherical drop of water has radius $1\, mm$ If surface tension of water is $70 \times {10^{ - 3}}\,N/m$ difference of pressures between inside and out side of the spherical drop is ........ $N/{m^{ - 2}}$

If the radius of a soap bubble is four times that of another, then the ratio of their excess pressures will be

Fill in the Blank :

$(i)$ Bubble in water have .......... free surface.

$(ii)$ Bubble in air have .......... free surface.

$(iii)$ Rain drop have .......... free surface.

The excess pressure in a soap bubble is thrice that in other one. Then the ratio of their volume is

The surface tension of soap solution is $25 \times {10^{ - 3}}\,N{m^{ - 1}}$. The excess pressure inside a soap bubble of diameter $1 \,cm$ is ....... $Pa$

A soap bubble in vacuum has a radius of $3 \,cm$ and another soap bubble in vacuum has a radius of $4 \,cm$. If the two bubbles coalesce under isothermal condition, then the radius of the new bubble is ....... $cm$