physics
posted by allen .
A sound registers 77.9 decibels on a detector. What is the intensity in W/m2? Assume the threshold of human hearing is 1.0×1012 W/m2. Give your answer in picowatts/m2.
1 pW = 1×1012 W/m2

77.9 = 10 log I/10^12 = log I/10^11
7.79 = log (I*10^12)
10^7.79 = I * 10^12
6.17 * 10^7 = I * 10^12
I = 6.67 * 10^5 W/m^2
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