A certain number of spherical drops of a liquid of radius r coalesce to form a single drop of radius R and volume V. If T is the surface tension of the liquid, then
energy = 4VT $\left( {{1 \over r} - {1 \over R}} \right)$ is released.
energy = 3VT$\left( {{1 \over r} + {1 \over R}} \right)$ is absorbed.
energy = 3VT$\left( {{1 \over r} - {1 \over R}} \right)$ is released
energy is neither released nor absorbed.
