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Homework Help: Finding Wavelength

  1. Feb 17, 2008 #1
    I have to answer this question in Physics: A mosquito flaps its wings at 600 vibrations a second, find the wavelength...

    What I thought to solve it was to take 340 meters per second divided by 600 Hz...which equals roughly .6.... is that correct? If so another problem states that Radio Waves travel at the speed of light 300,000 km/s...What is the wavelength of radio waves received at 100 MHz...I thought 300000/100...maybe?


    Last edited: Feb 17, 2008
  2. jcsd
  3. Feb 17, 2008 #2
    based on the equation wavelength = velocity/frequency I believe you are correct for the bug. make sure your units are converted to m/s and into hz for the second problem. I can't remember the magnitude of a mega-hz so you may be correct in saying they cancel out to Meters, but I would say you are using the formula correctly
  4. Feb 17, 2008 #3

    I think that is the equation you will need. Put the numbers you have into in, and rearrange. =]
  5. Feb 17, 2008 #4


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    Use [itex]c=f \lambda[/itex]

    all EM waves travel at c=3x10[itex]^8[/itex] and the prefix-M (Mega) is [itex]10^6[/itex]
  6. Feb 17, 2008 #5
    so its 300000/1000000?
  7. Feb 17, 2008 #6
    A megaherz is 10^6 Hz, so 100 Mhz is 10^8. Better use exponential notation than
    all those zero's. If you want the wavelength in meters, you have to convert the
    speed of light in m/s.
  8. Feb 18, 2008 #7

    Not exactly but you are on the right lines:

    300,000 km/s = 300,000,000 m/s
    100MHz = 100,000,000 Hz or 100,000,000 [1/s]

    [300,000,000 / 100,000,000] = [m/s]/[1/s] = [m]

    So you will get a answer in metres if you divide the Speed of light in m/s with the number of hertz.
  9. Feb 18, 2008 #8
    Thanks...so its 3 meters...thanks..
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