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Homework Help: Facts about mirrors and lens

  1. May 9, 2012 #1
    1. The problem statement, all variables and given/known data
    I am studying for my final and just want some clarification on mirror facts.

    2. Relevant equations

    3. The attempt at a solution
    Convex: focal length = negative and concave is opposite positive
    Diverginging = - image dist converging just the opposite or positive
    if an image is on the same side then the image distance is negative. If it is on the opposite side then positive
    spherical has a negative focal length
    if an image dist is neg then the image is virtual and upright
    if image dist is pos then image is real and inverted
    also magnification can tell me if the image is upright or inverted is it is pos then upright otherwise inverted. If magnification is postive the image distance is negative. I know ray diagrams help a lot but I need facts. Is there more that I am missing?
  2. jcsd
  3. May 9, 2012 #2
    Can someone tell me if im on the right track
  4. May 10, 2012 #3


    User Avatar

    Staff: Mentor

    I'd be cautious about stating a spherical mirror has a negative focal length. Most of the mirrors used in school lab experiments are termed spherical mirrors, being pieces of a sphere. They can be silver coated on the "inside" or the "outside" to make concave or convex mirrors, and are cheaper to manufacture than a parabolic mirror.

    I can see that you are thinking of a complete mirrored sphere, but "we" aren't necessarily thinking of a complete sphere when speaking of a spherical mirror.
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