Problem

A police car siren measures 70 dB to someone 44 meters away. What is the sound level of the police car is the police car is 1 meter away from the person? Round to the nearest decibel.

Police siren.jpg

Solution

There are two formulas that are useful for this problem.

1)

where

2)

First, solve for the intensity at 44 meters.

Second, solve for the power, which is the same at any distance away from the sound source.

Third, solve for the intensity at 1 meter.

Lastly, calculate the sound level in decibels.

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