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Homework Help: Wave Speed Equation

  1. Jan 17, 2007 #1
    I was hoping somebody could help me with the "wave speed" equation relating to the EM spectrum.

    The equation is:
    Speed = Frequency x wavelength (v=fλ)

    I believe the speed of all EM waves is 3 x 108

    this all seems simple enough, however i find putting this into practice somewhat complicated.

    For instance; "A radio frequency has a frequency of 92.2 x 106 Hz. Find its wavelength" How would I go about tackling such a question? If anybody could give me a step by step guide I'd be eternally greatful!

  2. jcsd
  3. Jan 17, 2007 #2


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    Staff Emeritus
    Science Advisor

    Well, rearrange the equation, to give [itex]\lambda=\frac{v}{f}[/itex], then plug in the numbers.
  4. Jan 17, 2007 #3

    Thanks, but what exactly must I do. Any chance of a step by step guide of how you'd do it?
  5. Jan 17, 2007 #4


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    Staff Emeritus
    Science Advisor

    Well, that pretty much tells you! You rearrange the formula, then put in the value of v and the value of f. You divide the value of v by the value of f and you have [itex]\lambda[/itex]. What particular part don't you understand?
  6. Jan 18, 2007 #5
    Thanks, I think I was just going through a phase of thinking too hard without taking a step back and lookinga at the bigger picture. I fully understand now!
  7. Aug 6, 2010 #6
    I am sorry for interuptting but i am now starting physics in form 4 but don't seem to understand .....watching the question you used as a example ...what is v then
  8. Aug 6, 2010 #7
    v is the velocity of the wave, which for any electromagnetic wave (light, radio, micro, gamma, etc) is c, the speed of light (3x10^8 m/s).
  9. Aug 6, 2010 #8
    orrr ok...thankssss....now understand.....
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