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Noir
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Homework Statement
What is the sound intensity 2.5m away from a 50W speaker? (Assume sound is spread out in a sphere) The intensity level 12.0m from a loudspeaker, placed out in the open, is 100 dB, what is the acoustic power output (in Watts) of the speaker?
Homework Equations
[tex]I =10^{\frac{B}{10} - 12}[/tex]
[tex]v =\frac{P}{A}[/tex]
The Attempt at a Solution
I = P / A
I = 50 / (4 * pi * 2.5 ^ 2)
I = 0.64 W / m ^ 2
If the inensity level is 100 dB, then the Sound intensity is 10 ^ -2 W / m ^ 2.
So, If I = P / A
I x A = P
P = 10 ^ -2 x (4 * pi * 144)
P = 18.2 Watts
Is this correct? The 18.2 Watts looks a little for a speaker putting out 100 dB at 12 m...
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