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Homework Help: Harmonics terminology for an open-closed tube

  1. Apr 22, 2010 #1
    1. The problem statement, all variables and given/known data
    When you have an open-closed tube, I was taught in high school that when using the equation

    λ = 4L/m, m = 1, 3, 5, 7, ... where m = 1 corresponds to the fundamental mode.

    I was taught that m = 1 is the 1st harmonic, m = 3 is the 3rd harmonic, etc.

    But my physics prof says m = 1 is the 1st harmonic, m = 3 is the 2nd, m = 5 is the 3rd, and so on. I'm just really confused about which one is right... can anyone explain?

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Apr 22, 2010 #2
    m=3 is the second harmonic because when m=2 then it's a closed tube.
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