Question

Desert cooler works better on a hot day.why

Answer 1

A desert cooler cools better on a hot dry day because on a hot dry day temperature is high and humidity is less which helps in better evaporation Due to the higher rate of evaporation it gives better cooling effect.

Answer 2

The particles of liquid in desert cooler absorb energy from the surrounding to regain the energy lost during evaporation. In summer this is fast. Hence desert cooler cool better in a hot dry day.