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A sound registers 77.9 decibels on a detector. What is the intensity in W/m2? Assume the threshold of human hearing is 1.0×10-12 W/m2. Give your answer in picowatts/m2.

1 pW = 1×10-12 W/m2

  • physics -

    77.9 = 10 log I/10^-12 = log I/10^-11

    7.79 = log (I*10^12)

    10^7.79 = I * 10^12

    6.17 * 10^7 = I * 10^12

    I = 6.67 * 10^-5 W/m^2

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