- #1
physicsnewby
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Homework Statement
A person is a certain distance away from a plane with three equally noisy engines at 120 dB. What is the sound intensity if two of the engines are shut off?
Homework Equations
B (in dB) = log I/Io
The Attempt at a Solution
using this equation:
120 dB = 10 log I/Io
10^12 = 10 log (I/10^-12 W/m2)
I = (10^12)(10^-12)
I = 1 W/m2
So, intensity for three engines is 1 W/m2. If two engines turned off, then I'm pretty sure you don't divide the answer by three to get 0.33 W/m2 per engine because the answer is 116. I can't figure out what I'm doing wrong.