For evaporation water pressure (excess pressure due to surface tension) is greater than vapor pressure. ⇒ Excess pressure in drop ≥ vapor pressure ⇒
2T
R
≥p where, T= surface tension p= vapor pressure R= Radius of drop ⇒R=
2T
p
Here, surface tension, T=8×10−2N∕m vapor pressure, p=25×103‌Pa Hence, radius of drop R=