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
Verified Correct Answer: A.
Physical Principles & Numerical Solution
In general 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
Source: Myschool Past Questions Archive (Record #12284)