Answer:
option E
Explanation:
given,
decibel level of a busy freeway = 100 dB
when flow is = 100 car/minutes
traffic flow= 20 car/minute
Intensity factor =[tex]\dfrac{I}{I_0}[/tex]
=[tex]\dfrac{20}{100}[/tex]
=[tex]\dfrac{1}{5}[/tex]
[tex]\Delta \beta = 10 log\dfrac{I}{I_0}[/tex]
[tex]\Delta \beta = 10 log\dfrac{1}{5}[/tex]
[tex]\Delta \beta = - 6.989\ dB[/tex]
The late night decibel level
= 100 - 6.989
= 93
The correct answer option E