Question

If the intensity level by 15 identical engines in a garage is 100 dB, what is the intensity level generated by each one of these engines?
a) 44 dB
b) 67 dB
c) 13 dB
d) 88 dB

Answer 1

To develop this problem it is necessary to apply the concepts related to Sound Intensity.

By definition the intensity is given by the equation

$\beta = 10Log(\frac{I}{I_0})$

Where,

I = Intensity of Sound

$I_0$= Intensity of Reference

At this case we have that 15 engines produces 15 times the reference intensity, that is

$I= 15I_0$

And the total mutual intensity is 100 dB, so we should

$\beta = 100-10*log(\frac{15I_0}{I_0})$

$\beta = 100-10*log(15)$

$\beta = 100-11.76$

$\beta = 88.23dB$

Therefore each one of these engines produce D. 88dB.