Explain how dew and fog are formed. OR
Write a short note on formation of dew and fog.

Explanation

At a particular temperature , a given volume of air can contain a certain maximum amount of water vapour.Normally , the temperature of air during the day is such that air is not saturated with water vapour present in it.
As the temperature falls, the capacity of air to hold water vapour becomes less.During a cold night,the temperature of air may fall to the dew point, or even below the dew point. If the temperature falls below the dew point, the excess of water vapour in air condenses on the surfaces of cold bodies and dew is formed. If thewater vapour condenses on the fine dust particles present in the atmosphere, mist of fog is formed.