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Homework Help: Relating Image Distance and Image Height

  1. Sep 6, 2008 #1
    Regarding the thin lens equation,

    1/s + 1/s' = 1/f

    where s= distance of object from lens, s' = distance of image from lens, and f=focal length, can h and h' (h = height of object and h' = image height) be substituted from s and s'? I know the values are related through similar triangles, I am just not positive that they can be substituted in this equation. Could anyone shed some light on this being a valid substitution?
  2. jcsd
  3. Sep 6, 2008 #2


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    You can't replace image distances with image heights in the thin lens equation but they are related by transverse magnification.

    [tex] M_T = \frac{y_i}{y_0} = -\frac{s_i}{s_0}[/tex]

    This occurs because in geometrical optics they both form sides of similar right triangles.
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