Posted by Anisha on Thursday, March 10, 2011 at 4:56am.
A loud speaker emits energy in all directions at a rate of 2.75 J/s . What is the intensity level at a distance of 25 m?

Physics  drwls, Thursday, March 10, 2011 at 7:00am
Divide the total power emitted (2.75 W) by the area of the sphere at that distance, 4*pi*R^2
With R in meters, that will give you the sound intensity in W/m^2 Usually designated by I) . I get I = 3.5*10^4 W/m^2
There is a formula for converting that to decibels. I get 85 dB
dB = 10 log(10) I/10^12
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