Give reasons for the following:
$(a)$ Water droplets appear on the outer surface of a tumbler containing ice-cold water.
$(b)$ People prefer to wear cotton clothes in summer.
$(c)$ On a hot sunny day,people sprinkle water on the roof or open ground.

(N/A) The water vapour present in the air,upon coming in contact with the cold surface of the glass tumbler,loses energy,gets condensed,and converts into liquid water droplets.
$(b)$ Cotton is a good absorber of water. It absorbs sweat from our body and exposes it to the atmosphere for easy evaporation. This process of evaporation causes a cooling effect on our skin.
$(c)$ The sprinkled water evaporates by absorbing a large amount of latent heat of vaporisation from the roof or open ground and the surrounding air,which results in the cooling of the area.