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Homework Help: Converging and diverging lenses

  1. Apr 28, 2008 #1
    1. The problem statement, all variables and given/known data
    a) A converging lens with a focal length of 15cm has an object 5cm tall placed 40cm to the left of it. To the right, 30 cm away, is a converging lens of focal length 10cm. use the thin lens and magnification formulae to locate the finale image. Find its magnification.

    b) Repeat part A for a -10cm diverging lens.

    2. Relevant equations
    1/f = 1/di + 1/do
    m = -(di/do)
    m = hi/ho

    3. The attempt at a solution
    i tried using a scaled diagram but im still pretty lost.....please help!
  2. jcsd
  3. Apr 28, 2008 #2


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    Homework Helper

    Once you find the image of the first lens (treating it like any other single lens problem), then the image of the first lens becomes the object of the second lens, and so you can find its image (which will be the final image). You might have to be careful of the sign conventions.

    For the total magnification, you find the magnification of each lens just as in a single lens problem. Once you have the separate magnifications, what would be the total magnification?
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