Question

A surface receiving sound is moved from its original position to a position three times farther away from
the source of the sound. The intensity of the received sound thus becomes
A. nine times as high.
B. three times as low.
C. nine times as low.
D. three times as high.

Answer 1

By Inverse Square law of Intensity of the sound.

The Intensity is inversely proportional to the square of the distance of the source.

So if it is moved three times away, it will be reduced by nine times.

So answer is  (C) Nine times as low

Answer 2

Correct answer choice is :

C) Nine times as low.

Explanation:

Sound intensity level also identified as acoustic intensity is described as the energy taken by sound waves per unit area in a path perpendicular to that area. The SI unit of intensity, which involves sound intensity, is the watt per square meter (W/m2). The loudness of a sound describes the intensity of any given sound to the intensity at the start of sound. It is marked in decibels (dB).