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Sound intensity using decibel values

  1. Nov 25, 2009 #1
    okay so I am having trouble with my sound ISU (independent study unit). Though my teacher said he would help, when i asked he said he cant...

    what i need to find is the sound intensity for the following decibel values..
    a) 100dB
    b) 55dB

    now the only relevant equation would be [tex]\beta[/tex]= 10 log (I[tex]_{}2[/tex]/I[tex]_{}1[/tex])
    and I[tex]_{}1[/tex]=1.0x10^-12 W/m^2

    i have attempted multiple times but cant seem to come to the correct answer
    the textbook gave the answers but no solution
    a)0.10 W/m^2
    b) 3.2x10^-7 W/m^2

    a) what i tried was subsituting [tex]\beta[/tex] for 100dB and I[tex]_{}1[/tex]=1.0x10^-12 W/m^2
    but from there im not quite sure what to do

    help me please!!!!
  2. jcsd
  3. Nov 25, 2009 #2
    You'll need to post more details. What answers are you getting? What did you try? Show step-by-step. Also, check that you copied the book answer correctly for (a).

  4. Nov 27, 2009 #3


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    Welcome to Physics Forums.
    You're on the right track. Can you post the equation you get when you make that substitution? You are trying to find I2 in the equation.
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