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Combinations of lenses

  1. Mar 19, 2007 #1
    Question regarding two lenses in combination - the first is a diverging lens with f = -31.5 cm, and the second is a converging lens, 14 cm away, with f = 20.0 cm. The exact question is 'Where will an object at infinity be focused?' (coming in through the diverging lens), and I kind of understand how to do it, but I have no idea how to factor in the distance of 14 cm. Please help.
  2. jcsd
  3. Mar 19, 2007 #2


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    If you find where the image from the diverging lens is, you use the 14 cm to help find where the "object" distance is for the converging lens so you can then find the second image distance.
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