Give reason for the increase in rate of evaporation of a liquid when air is blown above the liquid.

Short/Brief Note

When air is blown above the liquid, the speed by which the vapours move increases. Hence the rate of evaporation increases.
When the surface area is increased, rate of evaporation also increases. This is because evaporation occurs among the molecules on the surface, not in the interior. This means; increasing the surface area will increase the chance of more molecules to evaporate.
As temperature increases, rate of evaporation also increases. This is due to increasing kinetic energy of the surface molecules which leads them to free and become vapour.

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Change of Liquid into Vapour State

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Chapter 6: Heat Transfer - Short/long Answer Questions [Page 120]

Chapter 6 Heat Transfer
Short/long Answer Questions | Q 9.1 | Page 120

Evaporation takes place only from the surface of liquid.

All molecules of a liquid take part in the process of evaporation.

Evaporation takes place at ................. .

Heat is ................... during boiling.

Cooling is produced in ....................

Match the column

Column A	Column B
(a) Blowing air increases	(1) Increase in intermolecular separation
(b) Increase in pressure increases	(2) Pendulum of a clock
(c) Thermal expansion	(3) Cooking utensils
(d) Invar	(4) Boiling point
(e) Pyrex glass	(5) Evaporation

Give reason for the increase in the rate of evaporation of a liquid when temperature of liquid is increased.

What is boiling? Explain it on the basis of molecular motion?

What is the change in average kinetic energy of molecules of a liquid during boiling at its boiling point?

How is the heat energy supplied to a liquid used during boiling at a fixed temperature?