Answer:
[tex]\mathbf{\beta = 123.75 \ dB}[/tex]
Explanation:
From the question, using the expression:
[tex]125 \ dB = 10 \ log (\dfrac{I}{I_o})[/tex]
where;
[tex]I_o = 10^{-12} \ W/m^2[/tex]
[tex]I = 10^{12.5} \times 10^{-12} \ W/m^2[/tex]
[tex]I = 3.162 \ W/m^2[/tex]
This is a combined intensity of 4 speakers.
Thus, the intensity of 3 speakers = [tex]\dfrac{3.162\times 3}{4}[/tex]
= 2.372 W/m²
Thus;
[tex]\beta = 10 \ log ( \dfrac{2.372}{10^{-12}} ) \ W/m^2[/tex]
[tex]\mathbf{\beta = 123.75 \ dB}[/tex]
