$(a)$ State one similarity and one difference between evaporation and boiling.
$(b)$ Account for the following:
$(i)$ We wear cotton clothes in summer.
$(ii)$ $A$ wet handkerchief is placed on the forehead of a person suffering from high fever.
$(iii)$ Wet clothes dry slowly during the rainy season.

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(N/A) Similarity: In both processes,a liquid is converted into vapours.
Difference: Evaporation is a surface phenomenon,whereas boiling is a bulk phenomenon.
$(b)$ $(i)$ Cotton is a good absorber of water. It absorbs perspiration from our body and exposes it to the atmosphere for evaporation,which causes a cooling effect.
$(ii)$ $A$ wet handkerchief placed on the forehead absorbs heat from the body as the water evaporates. This process of evaporation causes cooling,which helps in lowering the body temperature.
$(iii)$ During the rainy season,the humidity in the atmosphere is high. Since the air is already saturated with water vapours,the rate of evaporation decreases,causing wet clothes to dry slowly.

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