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Homework Help: Did I understand sound refraction (am I doing it right)?

  1. Dec 11, 2016 #1
    1. The problem statement, all variables and given/known data
    Moving through air, a wave hits a steady area of water with a angle of 13°. The velocity of the wave in air is 550 m/s and in the water 1650 m/s. What is the refraction angle of the wave? Does the angle move away or to the line of symmetry?
    Btw. I think I translated it correctly from Bosnian so correct me if it's wrong

    2. Relevant equations

    So I didn't understand it so I went looking on the internet and found out it has to do something with some Huygenss dude.
    Anyway this is what I went with :
    sinα/sinβ = c1/c2
    3. The attempt at a solution
    What I got was β = 41°(nearly)
    and the wave goes away from the line of symmetry
  2. jcsd
  3. Dec 11, 2016 #2


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    Staff: Mentor

    The translation is okay as far as it goes, but a couple of points need clarification: First, what is the 13° angle measured with respect to? Second, what is the "line of symmetry"? Is it the normal (perpendicular) to the interface between the two media?
    You should also have come across Snell and Descartes.
    Maybe you should keep a few more decimal places in your intermediate calculations; I get a value that is just a little bit larger than that assuming that the angles are measured with respect to the normal.
  4. Dec 11, 2016 #3
    Thanks for pointing that out. Yes the 'line of symmetry' should be the normal to the interface ( it's actually called that in my language but I didn't think it would apply to English too). And the angle is closed by the interface and normal.
    So I'm guessing that my attempt was correct. My result was 41°17'59,54'' and that's just a bit larger :D
    Thanks for the reply :)
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