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Homework Help: Energy and sound problem help!

  1. Jun 29, 2009 #1
    A sound wave with intensity of 80.1 dB is incident on an eardrum of Area = 0.7x10^-4. How much energy is absorbed by the eardrum in 4 minutes???

    I know this much..... Power = (Intensity)(Area)..so...P=(80.1)(0.7x10^-4)

    and Energy = (power)(time) so....E = (80.1)(0.7x10^-4)(240 sec) = 1.35

    However, this is not the correct answer. Am i not doing the right conversions or what?? What looks wring here? (the correct answer is 1.72)
  2. jcsd
  3. Jun 29, 2009 #2
    E = (80.1) ( dB ) (0.7x10^-4)(240 sec)

    I think that you must change unit db
  4. Jun 29, 2009 #3
    Yea I thought about that but i would have no idea how to convert dB to Hz or whatever it needed to be.
    Any thoughts??
  5. Jun 29, 2009 #4
  6. Jun 29, 2009 #5
    I'm a little confused about how to use this equation. I looked at the example on yahoo over and over but cant seem to figure out where some of those numbers are coming from.
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