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Homework Help: Sound Intensity of a Whisper?

  1. Nov 19, 2008 #1
    1. The problem statement, all variables and given/known data
    A. What is the sound intensity of a whisper at a distance of 3.5 m, in W/m2?
    I know that a whisper is approximately 20 dB and P = 10-10 W/m2.

    B. What is the corresponding sound intensity level in dB?

    2. Relevant equations
    I = Power/[(4pi)(3.5m)2)
    dB = 10 log (I/Io).

    3. The attempt at a solution
    I = 6.50*10-13

    dB = -1.87 (I used 10-12 W/m2 for Io)
  2. jcsd
  3. Nov 20, 2008 #2


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    dB level would depend on how far away you are. You know it's 20 dB at what distance from the whisperer?
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