. Assume that a drop of liquid evaporates by decrease
in its surface energy, so that its temperature remain unchanged. What should be the minimum radius of the drop for this to be possible? The surface tension is T , density of liquid is ρ and L is its latent heat of vaporization.
B: T/ρ L
C: 2T/ρ L
D: ρ L/T
The radius of the water drop is r unit.
Now the conservation of energy tells
Decrese in surface energy= heat required in vaporization.
Decrease in surface energy
The radius of the rain drop is 2T/pLunit.
Hence option (C ) is correct.