Ans. INTENSITY LEVEL
The difference between the loudness of the faintest audible sound and the loudness of an unknown sound is called intensity level or sound level of the unknown sound. •
From Eq. (3), the intensity level of an unknown sound is given by
Sound level = K logr- ...... (1)
Unit: The SI unit of intensity level or sound level is bel.
Note: bel is a very large unit of intensity level of a sound. Generally, a small unit called decibel (dB) is used. One bel is equal to 10 dB.