Question

Give reason: (a) A wet handkerchief is placed on the forehead of a person suffering from high fever. (b) Wet clothes dry slowly during rainy season (cloudy day). (c) We sweat more on a humid day than a dry day.

Answer 1

A- we place a wet handkerchief on the forehead of a person suffering from high fever because the wet handkerchief absorbs the heat of the body and tried to bring the body at room temperature.
B-because of the clouds the sun gets hidden behind the clouds and it unables the sun to absorb water and therefore the water molecules present in the clothes evaporate but very slowly.
C-no , we sweat equally on both the days but on sunny day the suns heat causes the sweat to get evaporated wheareas during humid day / cloudy day our sweat doesn't evaporate .

Answer 2

The water in the handkerchief absorb heat from forehead and water evaporates leaving the region low energetic (cool)
Wet clothes dry slowly in rainy season because the humidity is more in the surrounding so,here the concentration of water in cloth is greater than water in air so diffusion takes place but slowly as I compare in hot region the moisture in air is very low so here diffusion is faster.
As I told the moisture in air is very less and temperature high the diffusion occurs fastly to keep our body cool.When sweat comes it absorbs heat energy from surrounding making the area less energetic (cool).