If the distance from a point source of sound is doubled; by what factor does the intensity decrease?

A. 4.00
B. 2.00
C. 0.50
D. 0.25

Correct Answer:

Option A – 4.00

Explanation

In general, the intensity of a wave is the rate of flow of energy across unit area normal to the direction of propagation of the wave intensity α¹/_r² where r is the distance away from the point source. Thus if the distance from the point source of the sound wave is doubled, then the intensity will be decreased by a factor of 4