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Light from a star homework

  1. Jul 12, 2007 #1
    1. The problem statement, all variables and given/known data

    The light from a star reflects from a concave mirror with a radius of curvature of 1.70 m. Determine how far the image of the star is from the surface of the mirror.

    Speed of light = 3.0 x 10^8 m/s
    r = 1.7 m
    f = 0.85 m

    1/di + 1/do = 1/f........ and then i'm stuck b/c i don't know what di or do are
     
  2. jcsd
  3. Jul 12, 2007 #2

    Kurdt

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    A stars light is considered as coming from infinity.
     
  4. Jul 12, 2007 #3
    Okay... but that doesn't help me solve di or do...
     
  5. Jul 12, 2007 #4

    Kurdt

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    Well the star is the object isn't it. So the object distance is infinity.
     
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