The surface tension and vapour pressure of a liquid at 25^ C are 8 10⁻² Nm ⁻¹ and 2.5 10^3 ~Pa respectively. The radius of the smallest spherical water droplet which can from without evaporating at 25^ C is

Step-by-step solution

The drop will evaporate if the water pressure is greater than the vapour pressure P . As P = 2 ~S R , where R = radius of drop aligned & R = 2 ~S P = 2 8 10⁻² 2.5 10^3 =6.4 10⁻⁵ ~m & =64 m aligned