Unit of Humidity - Relative Humidity, Absolute Humidity & Specific Humidity

Introduction
In this chapter, we will study humidity and its units. Further we will study Relative and absolute humidity and see the difference between relative and absolute humidity. In this chapter, we will study about humidity measurement.
NOTE: Meaning of humidity in Telugu/humidity meaning in telugu is తేమ
Meaning of humidity in Tamil/humidity meaning in tamil is ஈரப்பதம்

What is Humidity?

Humidity is a scientific term, which means concentration of water vapor present in air. Humidity at any place is dependent on pressure and temperature. It can be stated as, saturation point of holding water vapor increases as temperature increases.

Also read -

• NCERT Solutions for Class 11 Physics
• NCERT Solutions for Class 12 Physics
• NCERT Solutions for All Subjects

Types of humidity

Generally, we talk about three types of humidity namely,

• Absolute humidity
• Relative humidity
• Specific humidity

What is absolute humidity?

Absolute humidity is defined as the total mass of water vapor present per unit volume of air. It does not take air into consideration. It is highly variable as it is dependent on temperature and pressure, so this way of measuring humidity does not fit in Chemical Engineering. It is given by the numerical formula:

What is meant by relative humidity?

The relative humidity is defined as the total mass of water vapor present in per unit volume of air but the difference lies in dependency on air. It takes air in consideration. It is a measure of water vapor in the air as the total percentage it could hold at specific temperature.

Also Read: NCERT Solutions for Class 6 Physics Chapter 15 Air Around Us

Difference between Absolute humidity and relative humidity

• Apart from taking temperature into consideration there are few basic differences between them.
• Absolute humidity is expressed in grams per cubic meter while Relative humidity is expressed in percentage.
• As Absolute humidity does not take air into consideration, it is not so accurate compared to relative humidity. Relative humidity gives a fair idea of humidity at a particular temperature.

In this way we can distinguish between absolute humidity and relative humidity.

Dew point Temperature

Dew point is the temperature at which water vapor at constant pressure condenses into liquid water at the same rate at which it evaporates.

• When temperature is lower than dew point then rate of condensation is greater than evaporation. The condensed liquid is called dew when condensed on the surface.

Also check-

• NCERT Exemplar Class 11th Physics Solutions
• NCERT Exemplar Class 12th Physics Solutions
• NCERT Exemplar Solutions for All Subjects

NCERT Physics Notes:

• NCERT Notes Class 11th Physics
• NCERT Notes Class 12th Physics
• NCERT Notes For All Subjects