1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Resulatant intensity level

  1. Aug 8, 2014 #1
    1. The problem statement, all variables and given/known data
    A source prodeuces sound of intensity level of 30dB .If another source prodeuces sound at the same time , what's the resultant level?


    2. Relevant equations



    3. The attempt at a solution

    the ans is 10 log (2##I_1## / (##I_0##)) = 33dB , but why not = 10 log (4##I_1## / (##I_0##)) .. beacuse when 2 sound waves superposed , the resultant amplitude is A+A= 2A , I is directly proportional to (A^2) ...
     
    Last edited: Aug 8, 2014
  2. jcsd
  3. Aug 8, 2014 #2

    olivermsun

    User Avatar
    Science Advisor

    Are the two sounds correlated (e.g., in phase) with each other? The sum of the two will only have amplitude A + A (and therefore +6 dB) if they are perfectly in phase with each other. In general they're assumed uncorrelated (they have nothing to do with each other), and so you add the intensities and get +3 dB.
     
  4. Aug 8, 2014 #3
    it's not 3db am i right? the intensity now it's 2I ?
     
  5. Aug 8, 2014 #4

    olivermsun

    User Avatar
    Science Advisor

    33 dB is +3 dB relative to the original 30 dB, right?

    Hint: log102 = ?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Resulatant intensity level
  1. Intensity levels (Replies: 1)

Loading...