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Homework Help: Which source is more intense?

  1. Apr 23, 2012 #1
    Two sound sources have intensities of 1×10^-11 W/m^2 and 1×10^-7 W/m^2, respectively.
    Which source is more intense?

    10 Log (10^-7)/(10^-12) = 50
    10 Log (10^-11)/(10^-12) = 10
    So 1×10^-77 W/m^2 is more intense.

    However the next question is by how many times more?

    Will someone please help me. Maybe I'm just tired, but I thought it was 4 but I am being told that is wrong. Thank you!
  2. jcsd
  3. Apr 24, 2012 #2
    Ok, for the first part, you dont need to take logs, Intensity is simply power/Area which is given to you as units in measurements.

    1x10[itex]^{-7}[/itex]W/m[itex]^{2}[/itex] is the correct answer simply because its a bigger number.

    For part 2 you have to convert them to dB which you have done in your part one (50dB and 10dB) You will double intensity level every 3dB so you just divide the difference by 3.
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