Two sound waves of slightly different frequently have amplitude ratio `11//9`. What is the different of sound levels in decibels of maximum and minmum intensities head at a point ?

Options

A. 100
B. 10
C. 16
D. 20

Answer

D

Explanation

`SL_(2) - SL_(1) = 10 log (l_(max))/(l_(min)) = 10 log [((sqrtl_(1) + sqrtl_(2))^(2))/((sqrtl_(1) - sqrtl_(2))^(2))]`
`=10 "log"(((a_(1))/(a_(2))+1)^(2))/(((a_(1))/(a_(2))-1)^(2))=20dB`