CBSE Class 9 Answered

(a)When acetone is poured on the palm, it takes up the latent heat of vaporisation required to change from the liquid state to vapour state from our hand. The hand loses heat and gets cooled.

(b)The earthen pot has small pores in its walls. Some of the water continuously seeps out from these pores. This water evaporates and absorbs heat of vaporisation from the remaining water. Thus, the remaining water loses heat and gets cooled.

(c) Larger the surface area, faster will be the cooling. Evaporation is a surface phenomenon. The particles of tea on the surface absorb the heat for vaporisation from the remaining particles of the tea and evaporate. The tea thus loses heat and cools faster.