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Homework Help: Wavelength, speed and frequency question

  1. Oct 20, 2014 #1
    1. The problem statement, all variables and given/known data

    Typical AM radio wavelengths are about as long as a football field, while typical FM radio wavelengths are about a meter long. Which one has the highest frequency? If AM wavelength is 100 times longer than an FM radio wavelength, then how do the frequencies compare? How do their speeds compare?

    The professor asked for a more conceptual answer than a mathematical one, would this be correct? Thanks in advance!

    2. Relevant equations

    speed=wavelength * frequency

    3. The attempt at a solution

    The FM radio waves have a higher frequency because their wavelength is smaller so there will be more waves per unit of time or unit of space. Their frequencies compare in the sense that FM radio waves are smaller than AM radio waves by a factor of 100 so for any given amount of time or distance there will be 100x more FM radio waves than AM radio waves. In terms of their speed; their speed is actually the same because all waves travel at the speed of light.

  2. jcsd
  3. Oct 20, 2014 #2
    Sounds good to me.
  4. Oct 20, 2014 #3


    User Avatar
    Gold Member

    Sounds good to me too, although you might amend your "all waves travel at the speed of light" to "all ELECTROMATIC waves travel at the speed of light (in a vacuum)"
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