Physics

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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?

  • Physics -

    100 Cars:

    db = 10*Log(I/Io)
    db = 10*Log(I/10^-12) = 80
    Log(I/10^-12) = 8
    10^8 = I/10^-12
    I = 10^-4 W/m^2.

    5 Cars:

    I = (5/100) * 10^-4 = 5*10^-6 W/m^2.

    db = 10*Log(5*10^-6/10^-12)
    db = 10*Log(5*10^6) = 67.

  • Physics -

    456

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