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Homework Help: Wavelength and Frequency with Temperature

  1. Apr 16, 2008 #1
    1. The problem statement, all variables and given/known data

    Two loudspeakers are 2.5 m apart. A person stands 2.9 m from one speaker and 4.0 m from the other. Assume the air temperature is 20°C.
    a) What is the lowest frequency at which destructive interference will occur at this point?

    (b) Calculate the next two frequencies that also result in destructive interference at this point.

    2. Relevant equations
    not sure if these apply:

    3. The attempt at a solution
    i have no idea how to get a start on this problem
  2. jcsd
  3. Apr 17, 2008 #2


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    What do you know about destructive interference?
  4. Apr 17, 2008 #3
    I think i figured it out:
    for destructive interference, one difference in distances is half of the wavelength.
    so 4-2.9=1.1
    then i use the equation with temperature, solve for the temperature at 20 degrees C
    and plug wavelength and velocity in the v=f*(lambda) equation.
  5. Apr 17, 2008 #4


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    For the rest of the problem, what other values can the difference in distances have?

    p.s. don't forget to show units consistently throughout your solution.
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