Question

In the afternoon, the decibel level of a busy freeway is 80 dB with 100 cars passing a given point every minute. Late at night, the traffic flow is only 5 cars per minute. What is the late-night decibel level?

Answer 1

Answer:

67 dB

Explanation:

given,

Sound in afternoon = 80 dB

Intensity of car,I₀ = 100 cars/ minute

Sound in the night = ?

Intensity of car,I = 5 car/minutes

using formula for sound calculation

 $\Delta \beta = 10 log(\dfrac{I}{I_0})$

 $\Delta \beta = 10 log(\dfrac{5}{100})$

 $\Delta \beta = 10 log(\dfrac{1}{20})$

 $\Delta \beta = 10 log(0.05)$

 $\Delta \beta = 10\times -1.30$

 $\Delta \beta = -13\ dB$

The late night decibel is equal to 80 dB - 13 dB = 67 dB