Is it possible to have a spherical drop of water that could evaporate without absorbing heat or losing internal thermal energy?
Given data:
Surface tension of water: 0.073 N/m
Density of water: 1000 kg/m3
Latent heat of evaporation: 2256 kJ/kg
1let us assume a drop of radius R m
if the drop breaks into very small drops of radius r energy will be released
so the surface energy of R must be greater than the energy required to evaporate the water
so we get R<0.09 x 10^ -9
so if this small drop breaks into very very smaller droplets(r→0)
the water will evaporate
66Your estimates are slightly off-beat. You should get R < 0.07 x 10-9 m. What can one conclude from here? The point is that this is less than the size of a water molecule!! That means we cannot have such a drop. Therefore, there does NOT exists a water drop which could evaporate without absorbing heat, or losing internal energy.