Q:

Surface energy of water

If $10^3$ small drops of water each of radius $10^{-7}\,\mathrm{m}$ combined to form one single large drop then what should be the energy ? If the surface tension is equal to $0.07\,\mathrm{N/m}$ . I think the surface area should decrease as energy is released , but how will we find the energy? Or how can we find radius of large drop to find $∆ A$ , $A$= surface area?

A:

I will only tell you how to proceed with the problem.

Volume is conserved. Equate the volume of the small spherical drops with that of the large drop and find the radius of the large drop.
Now you can find the surface area of the new large drop. You can also find the total surface area occupied by the many small drops before.
Hence calculate the change in surface area and input the proper formula/formulae to obtain the answer.

