Question

Give reason. 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.

Answer 1

a.
water vapours present in our enviornment got the temperature to change in liquid form.
b.
becuse in summers we tend to lot of sweat cotton clothes absorbs the sweat and give cooling. cotton clothes allows better air circulaton so it helps in absorbing of sweat and give cooling to the body.
c. because it evaporates and give cooling sensation

Answer 2

Answer:

(a) The water vapour present in the air, on coming in contact with the cold glass of water, loses energy and gets converted to a liquid state (gets condensed), which can be seen as tiny water droplets.

(b) In summer we perspire more. Cotton being a good absorber of water helps in absorbing the sweat and exposes it to the atmosphere for evaporation. When sweat evaporates from our body, it takes away the heat from our body. Thus, our body loses heat and gets cooled.

(c) The sprinkled water evaporates by taking large latent heat of vapourisation from the roof or open ground and surrounding air causing cooling of the place.