Answer:
I = 0.316 W/m^2
Explanation:
In order to calculate the intensity required to produce a sound level of 115 decibels, you use the following formula:
[tex]B=10log(\frac{I}{I_o})[/tex] (1)
B: sound level = 115dB
I: intensity of the sound = ?
Io: Threshold of hearing = 10^-12 W/m^2
You solve the equation (1) for I, by using properties of logarithms:
[tex]B=log(\frac{I}{I_o})^{10}\\\\10^{B}=10^{log(\frac{I}{I_o})^{10}}\\\\10^B=(\frac{I}{I_o})^{10}\\\\I=I_o10^{B/10}[/tex]
Finally, you replace the values of all parameters:
[tex]I=(10^{-12}W/m^2)10^{115/10}\\\\I=0.316\frac{W}{m^2}[/tex]
The intensity that produces a sound level of 115 dB is 0.316 W/m^2