The potential energy of a molecule on the surface of a liquid compared to the molecules inside the liquid is:

The radius of a soap bubble is $r$, and the surface tension of the soap solution is $T$. Without increasing the temperature, how much energy is required to double its radius (in $\pi r^2 T$)?

$A$ liquid drop having surface energy $E$ is spread into $729$ droplets of same size. The final surface energy of the droplets is

Two mercury drops,each with same radius $r$,merge to form a bigger drop. If $T$ is the surface tension of mercury,then the surface energy of the bigger drop is given by

Two small droplets combine to form a single large drop. What is the ratio of the surface energy of the small droplets to the surface energy of the large drop?

$A$ film of water is formed between two straight parallel wires of length $10 \ cm$ each,separated by $0.5 \ cm$. If their separation is increased by $1 \ cm$ while still maintaining their parallelism,how much work will have to be done? (Surface tension of water $= 7.2 \times 10^{-2} \ N/m$)