Ans. The unit of loudness is bel or decibel. Because human earxan hear wide range of intensities, measuring sound intensity level on a linear scale is not convenient for us. Hence, instead of linear scale, logarithmic scale is used for this purpose. For example; if the audible intensity range is measured on a ruler, the scale would extend from 1 foot (faintest) to above 3000 miles (loudest).