Chapter 13, Problem 13.67P

Interpretation Introduction

Interpretation:

The reason behind the milk not spilled when the straw is lifted out of the glass and spilled when the finger is removed has to be determined.

Concept Introduction:

The vapors of any liquid above its liquid phase exert pressure on the surface of the wall and the molecules in liquid phase known as vapor pressure. Till the time vapor pressure is less than the atmospheric pressure, vaporization process carries on and as soon as the vapor pressure becomes equal to atmospheric pressure, vaporization rate becomes equal to condensation rate. At this stage, vapors above the liquid phase are called equilibrium or saturated vapor pressure.

Air exert an atmospheric pressure equivalent to $1{\text{ N/1 m}}^2$.