Question

Unit of loudness is:
A. phon
B. Bel
C. both
D. none

Answer 1

Hint: In general the level of sound or intensity is expressed as the unit of decibel. But we cannot say loudness is not a sound intensity. It is a subjective word which describes the strength of the ear's perception for a sound.

Complete step-by-step answer:
Loudness of the determined by amplitude of the sound wave. The pressure level or the intensity of sound is measured using by decibels. Loudness of sound is measured using two units phonamel sone. phon is used on sounds heard at a 1 KHz level to a listener. If the sound seems to be decibel around 50 decibel then it is expressed as 50 decibel at 1 kHz simply 50 phon but on the other hand ,phon is a unit for measuring the loudness that in the opinion of a group of listeners is equal to 1KHz sound of intensity 40 decibels
Hence the unit of loudness is phon.
Option (a) is correct.

Note: In general we can say for measurement of any quantity we need a unit. For example if we measure any length we write it as 10cm or 10 m where cm or m is a unit of length. But if we write only 10 then we cannot say it represents length.