-Drupath Goutham, Subject Matter Expert at Edumarz
Solution: When a liquid evaporates, the particles of the liquid absorb energy from the surroundings to compensate the loss of energy during evaporation. Since evaporation causes cooling, this makes the surroundings cool.
On a hot dry day, the humidity will be low and the temperature will be high. The temperature of the air will be relatively higher and energy transferred will be more. Since the same volume of air will be circulated energy transferred per given volume of air will be more on a hot day. Evaporation will be faster resulting in better cooling. On a dry day, water vapor present in the air will be less, and the circulation of this air will provide faster cooling compared to a humid day. Humid air contains more water vapor content so energy transferred will be less and the rate of cooling will be less. Therefore, desert cooler cools better on a hot dry day.