Sound:- Intensity , Loudness , Unit of Loudness , Limits of Human Audibility

1. Loudness :- The loudness of sound is the characteristic of sound due to which it appears to be feeble or loud is known as loudness of sound . Loudness determines the degree of sensation that the sound produced in the ear .
2. Units of Loudness :- In the S.I. system of units , the loudness is expressed in terms of Bels . If intensity of a sound is increased by 10 times , then its loudness will be increased by 1 Bel , and if intensitybof sound is increased by 100 times , then loudness will be increased by 2 Bels . But , Bel is a big unit for the practical purpose , therefore a unit smaller than Bel , i.e. Decibel (db) , is used in practicals which is one tenth of the original unit Bel .               1 Bel = 10 Decibel 
3. Intensity :- The energy (Sound Energy) passing through a unit area around a particular point per second is called the Intensity of sound . The unit of intensity is: watt/m^2
4. Difference between Loudness and Intensity :- The loudness of sound is the degree sensation , whereas the intensity of sound is a physical quantity which is objective in nature , while the sensitivity of ear is subjective in nature .
5. Our ear , cannot hear infrasonic and ultrasonic sounds , whatever their intensity may be , therefore there is no relation between intensity of sound and our hearing , but the loudness is related to the sensitivity of our ear .
6. Limits of Human Audibility :- It is also known as the threshold of audibility . The minimum intensity of sound which can be hear by a human being is known as the Threshold of Audibility . Its value is 10^-12 watt/m^2 . The sound of intensity less than threshold of audibility can not be hear by human beings . In anybordinary talk , the intensity of sound is found to be nearly 10^-6 watt/m^2 .

Conclusion :- This was a knowledge about some common topics related to sound i.e. its intensity , loudness , unit of loudness , limits of human audibility etc. I hope that it was helpful to you and you liked it .

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