Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Sound Intensity Level Ratio

  1. Apr 22, 2008 #1
    [SOLVED] Sound Intensity Level Ratio

    1. The problem statement, all variables and given/known data

    The sound intensity level at a rock concert is 110 dB, while that at a jazz fest is 100 dB. Determine the ratio of the sound intensity at the rock concert to that at the jazz fest.

    2. Relevant equations
    B=(10dB) log(I/Io)

    3. The attempt at a solution

    110=(10db) log (I/1.0*10^-12)
    100=(10db) log (I/1.0*10^-12)

    dont know where to go from here
  2. jcsd
  3. Apr 22, 2008 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    Ok, well let I_0=10^-12, then you have two expressions (taking log base 10)

    [tex]110=10\log\left(\frac{I_1}{I_0}\right) \hskip1cm 100=10\log\left(\frac{I_2}{I_0}\right)[/tex] and you want to find the ratio [tex]\frac{I_1}{I_2}[/tex]. So, you need to perform some algebra on these expressions to make I_1 and I_2 the subject of the equations, respectively. Try dividing both sides of each equation by 10. After that you will need to take the inverse log of each side: how would you do this?
  4. Apr 22, 2008 #3
    That was my problem, I forgot you could do antilogs. thanks you so much
  5. Apr 22, 2008 #4


    User Avatar
    Staff Emeritus
    Science Advisor

    No problem!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook