If $T$ is the surface tension of a soap solution, then the amount of work done in increasing the diameter of a soap bubble from $D$ to $2D$ is: (in $\pi D^2 T$)

One thousand small water drops of equal radii combine to form a big drop. The ratio of final surface energy to the total initial surface energy is

The amount of work done to break a big water drop of radius $R$ into $27$ small drops of equal radius is $10 \ J$. The work done required to break the same big drop into $64$ small drops of equal radius will be (in $J$)

$A$ soap bubble of radius $r$ is blown up to form a bubble of radius $2r$ under isothermal conditions. If $T$ is the surface tension of the soap solution, what is the energy spent in blowing the bubble (in $\pi T r^2$)?

When a mercury drop of radius $R$ splits up into $1000$ droplets of radius $r$,the change in surface energy is ($\pi R^2 T$). ($T=$ surface tension of mercury).

$A$ film of soap solution is formed between two straight parallel wires of length $10 \,cm$ each, separated by $0.5 \,cm$. If their separation is increased by $1 \,mm$ while still maintaining their parallelism, how much work will have to be done? (Surface tension of solution $= 65 \times 10^{-3} \,N/m$)