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

Edited By Vishal kumar | Updated on Sep 24, 2024 09:57 PM IST

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

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What is Humidity?
Types of humidity
Difference between Absolute humidity and relative humidity

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

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 -

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:

$AH=\frac{m_h_2{^0}}{v_{net}}$

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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 Physics Notes:

Frequently Asked Questions (FAQs)

1. During which part of the year, it is most likely to form dew?

As we have read about Dew point, Dew forms on the surface when temperature cools down to the dew point. Formation of dew happens when dew point is below the freezing point, so generally dew is most likely to form during winter days.

2. What it means when it is said- Relative humidity is 100% saturated.

Relative density is the ratio between water vapor present in a given volume of air compared to water vapor present at a saturated level at given pressure and temperature, so when the ratio comes to be 1 then it means Relative humidity is 100% saturated.

3. What measures humidity in the air?/air humidity measurement is done by which instrument?

Hygrometer used to measure humidity in the air.

4. Write the humidity symbol

RH(relative humidity) is the humidity symbol.