A sound intensity of 70 dB is observed at a distance d from the source of sound.What sound intensity would be observed at a distance 2d from the source?
A)68 dB
B)67 dB
C)64 dB
D)62 dB

Question

Quizplus · Accepted Answer

Sound intensity decreases with distance from the source according to the inverse square law. This means that at a distance of 2d, the sound intensity will be reduced to 1/4 (or 6 dB lower) of the original intensity at distance d.

Using the formula I2 = I1/(d2/d1)², where I1 is the initial intensity, d1 is the initial distance, I2 is the final intensity, and d2 is the final distance, we can calculate the new sound intensity:

I2 = 70 dB / (2/1)²
I2 = 70 dB / 4
I2 = 17.5 dB

Taking into account that the decrease in intensity is 6 dB, we can subtract this from the initial intensity of 70 dB to obtain:

I2 = 70 dB - 6 dB
I2 = 64 dB

Therefore, the new sound intensity observed at a distance of 2d from the source is 64 dB.

A Sound Intensity of 70 DB Is Observed at a Distance