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Time for a micro-wave to travel a distance

  1. Dec 2, 2008 #1
    This is the last part of the question. I already found the frequency to be 9.7 GHz and the wavelength is .031 meters. It's just this last part of the question that I can't seem to figure out. I really don't even know where to begin, I checked my book and online and can't seem to find any relevant equations to use...

    1. The problem statement, all variables and given/known data

    Microwave signals are beamed between two mountaintops 54 apart. How long does it take a signal to travel from one mountaintop to the other?
    My answer has to be in the units ms.
    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Dec 2, 2008 #2
    Seriously, ANY ideas would be of help at this point..
  4. Dec 2, 2008 #3
    Well, you know the distance and you want the time taken to travel the distance. What else would you need to know to calculate the time?
  5. Dec 2, 2008 #4
    speed of the wave?
  6. Dec 2, 2008 #5
    Micro waves are electromagnetic waves which travel at the speed of light in a vacuum. It sounds like you can assume this speed for this calculation.
  7. Dec 2, 2008 #6
    So I should divide the speed of light by 54000m?
  8. Dec 2, 2008 #7
    What do you think?

    Consider dimensional analysis. Do the dimensions of time fit the dimensions of distance divided by those of speed?
  9. Dec 2, 2008 #8
    I really don't understand what you're saying... = /
  10. Dec 2, 2008 #9


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    Homework Helper

    Your distance is in units of length - L.

    Your basic speed of light is in units of length over time L/T.

    If you divide L/T by L you would get 1/T wouldn't you?
  11. Dec 2, 2008 #10
    When I divided the speed of light (299,792,458 m/s) by my distance (54km or 54,000m), I got 5551.7 and this was not the correct answer. I then set my 5551.7 equal to 1/T and solved for T. By doing this I came up with 1.79 * 10^-4. This was incorrect as well. = /
  12. Dec 2, 2008 #11


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    Homework Helper

    The answer is looking for units of milliseconds.
  13. Dec 2, 2008 #12
    Ahh, genius! I converted the units and it worked! Thanks SO much!
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