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Help w/ constructive interference sound wave intensity

  1. Feb 12, 2007 #1
    The Problem : The sound wave with intensity 31 mW/m2 interferes constructively with a sound wave that has an intensity of 20 mW/m2. What is the intensity of the superposition of the two.

    I know that you can add the amplitudes for constructive interference or subtract for destructive interference . Also i do know that intensity is proportional to amplitude squard. I dont know how to solve when i only have two intensities so i know you cant just add the intensitites. any help would be appreciated thanks

  2. jcsd
  3. Feb 12, 2007 #2
    This may be a bit of a trick question; if the two waves were set up with equal amplitudes to collide constructively, what would be your guess? Double, nothing, or somewhre in between? Pressure is a scalar quantity,
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