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Homework Help: A couple of optics questions

  1. Sep 9, 2003 #1
    1. Imagine that you are standing 5 ft from and looking directly toward, a brass ball 1 foot in diameterhanging in front of a pawn shop. Describe the image you would see in the ball.

    -Would I have to find the an answer that tells me that it is inverted, real, virtual, etc?

    2. What formula would I useto find the radius of curvature? if the magnification of a keratometer is found to be 0.037X when the object distance is se at 100 mm, what is the radius of curvature?
  2. jcsd
  3. Sep 9, 2003 #2


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    Staff Emeritus

    Mirror problems are a little difficult to do in a forum. It really helps to have a picture. I highly suggest you do a google search on convex mirrors and look at the examples done in your physics book. For this types of problems DRAW A PICTURE and make sure you label everything

    The equation you would use is
    1/s' + 1/s = 1/f where 1/f = 2/R

    R is the radius of curvature
    f is the focus
    s is the distance from your eye to the front of the mirror
    s' is the distance from the front of the mirror to the image (may it be real or virtual)

    m = -s'/s where m is the magnification
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