Question

define humidity
and what is mixture

Answer 1

Humidity is the amount or the relative proportion of water vapor in air in our atmosphere.

Higher the humidity more uncomfortable we feel. After a rain the atmosphere is more humid.  Dry air is less humid.  Humidity of 30% may be okay to tolerate.
Humidity could spoil some metals.

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A mixture is a physical mixing of different elements and compounds in required proportions.  The mixed substances do not react chemically. Their physical appearance may change to some other color than the individual colors. Or, one of the substances dominates the mixture. 

A mixture can be separated by simple physical means or by dissolving in a solvent and evaporating also.

Example : mix salt and sugar.

Answer 2

$Hi$

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The water content in the atmosphere is called humidity .

The actual amount of water present in the atmosphere is called absolute humidity . It is measured as the amount of water vapour present per cubic metre volume of air (g/m³) .

Factors influencing the amount of moisture present in the air :

✓Temperature

✓Time

✓Water bodies

There is a limit to the amount of water vapour the atmosphere can hold at a certain temperature . The stage at which the atmosphere is fully saturated with water is termed as saturation level .