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shards5
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Homework Statement
A spherical source radiates sound uniformly in all directions. At a distance of 9 m, the sound intensity level is 100 dB. What power is radiated by this source?
Just a simple answer check to see if my answer is reasonable.
Homework Equations
[tex]\beta[/tex] = 10 db log (I/I0)
Intensity = power/area
The Attempt at a Solution
First convert the given decibels to Intensity then convert the found intensity to power via the second equation.
100 dB = 10 dB log (I/(1*10^-12)
Divide by 10 on both sides.
10 = log ((I/(1*10^-12)
Raise both sides to the tenth power to get rid of log
1010 = (I/(1*10^-12))
Multiple both sides by 1*10-12 I get. . .
I = 0.01 (Can someone confirm that I doesn't have units?)
Plugging in I to the second equation I get. . .
0.01 = [tex]\frac{Power}{4*\pi*9^2}[/tex]
Divide both sides by area I get Power. . .
Power = 10.178 (I know the units should be watt but if Intensity has no units and area only gives m2 then how do I get the units for watt? Does this mean this is wrong?)
Thanks in advance for your help.