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Homework Help: Sound waves and eardrum problem

  1. Mar 8, 2006 #1
    A 50 dB sound wave strikes an eardrum whose area is 4.1 * 10-5 m2.
    (a) How much energy is absorbed by the eardrum per second?
    W
    (b) At this rate, how long would it take your eardrum to receive a total energy of 1.0 J?
    years

    I have tried to solve using I=2pi^2f^2A^2pv

    and got f=280 ; v=343;p=1.29;I=1*10^-12 and A =1.28e-18 its wrong though
     
  2. jcsd
  3. Mar 8, 2006 #2

    Andrew Mason

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    Science Advisor
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    Decibels are a little tricky to work with. I think all you need to know is that [itex]I = 10 log(P/P_0) [/itex] where P is the power/area and [itex]P_0 = 10^{-12} W/m^2[/itex]

    AM
     
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