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Homework Help: Fundamental frequency and temperature

  1. Mar 5, 2010 #1
    1. Balboa Park in San Diego has an outdoor organ. When the air temperature increases, the fundamental frequency of one of the organ pipes _____.

    a) goes down
    b) stays the same
    c) goes up
    d) is impossible to determine




    2. v=331sqrt(1+t/273)/



    3. goes up?)
     
  2. jcsd
  3. Mar 5, 2010 #2

    ehild

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    How are the frequency, wavelength and speed of the sound wave related?

    ehild
     
  4. Mar 7, 2010 #3
    v=lamda x f.
    however we know that in same medium velocity of propagation is constant but i dunno if that means less dense air due to heat means same medium.also we know that for any source of oscillation frequency is constant but there is not sound source here it is air blowing.If temperature goes up velcoity goes up if lamda is constant then frequency goes up but im not sure.Any help in this mess.?
     
  5. Mar 7, 2010 #4

    lightgrav

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    What is the "cause" of the sound wave having a frequency?
    how much (%) do the organ pipes length change, if 10 degrees warmer?
     
  6. Mar 7, 2010 #5

    ehild

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    The sound source is the organ pipe. The wavelength of the sound is determined by the length of the pipe. When it is blown, standing waves form in it, and the wavelenght of the fundamental frequency is twice the pipe length of an open pipe and 4 times the length of a closed one. This length changes so little with increasing temperature, that you think the wavelenght does not change as the temperature rises. The speed of sound does change, you have the formula for v: it rises. v and f are proportional: you are right, f goes up with the rising temperature.

    ehild
     
  7. Mar 8, 2010 #6
    Thanks for your help.:) i got it now"how v is proportional to f " through f=nv/2l.
    Thanks for everyone.
     
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