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Homework Help: Speed of light; distance from earth to sun

  1. Sep 6, 2006 #1
    Ok, I got this problem and I don't know where to start...

    "The average distance from the earth to the sun is 9.30 x 10^7 miles. Light travels at a speed of 3.00 x 10^8 meters per second. If the sun were to be suddenly extinguished, how many minutes would it take for the effect to be visible here on earth? Show work."

    Can someone tell me how do I start?
  2. jcsd
  3. Sep 6, 2006 #2


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    Hi there lonelyassassin and welcome to PF,


    [tex]Speed = \frac{Distance}{Time}[/tex]
  4. Sep 6, 2006 #3
    Ok, from your hint, I got:
    http://img339.imageshack.us/img339/8793/work1bu5.jpg [Broken]

    First of all, am I on the right track?
    If I am, then the next step should be to factor label to get to minutes, but the meter/second is on both the denominator and numerator. And the miles is already on the numerator.

    Can you tell me how to proceed now?
    Last edited by a moderator: May 2, 2017
  5. Sep 6, 2006 #4
    Convert miles to meters or convert meters/second into miles/second and you'll have your answer.
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