Solution:
To calculate the pressure ratio for a sound for measuring sound, we use the following logarithmic formula of Sound Pressure Level (SPL):
SPL = [tex]20\log_{10}\frac{p}{p_{ref}} dB[/tex]
where,
p = pressure to be measured
[tex]p_{ref} [/tex] = reference pressure
[tex]\frac{90}{20}[/tex] = [tex]\log_{10}\frac{p}{p_{ref}} dB[/tex]
[tex]10^{4.5}[/tex] = [tex]\frac{p}{p_{ref}}[/tex]
pressure ratio is :
[tex]\frac{p}{p_{ref}}[/tex] = [tex]3.16\times 10^{5}[/tex]
