The surface tension and vapour pressure of water at 20^(@)C is 7.28xx10^(-2)Nm^(-1)and2.33xx10^(3) Pa ,respectively .What is the radius of the smallest spherical water droplet which can form without evaporating at 20^(@)C?

The surface tension and vapour pressure of water at 20^(@)C is 7.28xx1

1.	The surface tension and vapour pressure of water at 20^(@)C is 7.28xx10^(-2)Nm^(-1)and2.33xx10^(3) Pa ,respectively .What is the radius of the smallest spherical water droplet which can form without evaporating at 20^(@)C?
Answer» <P> Solution :Surface tension of water `S=7.28xx10^(-2)N//m` Vapour pressure `P=2.33xx10^(3)P_(a)` The drop will evaporate if the water pressure on liquid is GREATER than vapour pressure above THESURFACE of liquid. Vapour pressure without evaporation =excess pressure in a drop `P=P_(i)-P_(o)` `P=(2S)/(R) "" (because "For drop"P_(i)-P_(o)=(2rho)/(R))` `thereforeR=(2S)/(P)` `thereforeR=(2xx7.28xx10^(-2))/(2.33xx10^(3))` `R=6.25xx10^(-5)m`