If $450 \text{ erg}$ of work is done in blowing a soap bubble of radius $r$, the additional work required to be done to blow it to a radius equal to $3r$ is (in $\text{ erg}$)

Consider a soap film on a rectangular frame of wire of area $4 \times 4 \text{ cm}^2$. If the area of the soap film is increased to $4 \times 5 \text{ cm}^2$,the work done in the process will be (The surface tension of the soap film is $3 \times 10^{-2} \text{ N/m}$).

The surface tension of a liquid is $0.5 \, N/m$. If a film is held on a ring of area $0.02 \, m^2$,its surface energy 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 $\pi r^2 T$)?

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

$A$ liquid drop having surface energy $E$ is spread into $216$ droplets of the same size. The final surface energy of the droplets is (in $E$)