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What is the focal length of the lens?

  1. Apr 3, 2009 #1
    1. The problem statement, all variables and given/known data
    When a diverging lens is held 12 cm above a line of print, as in Figure 26.29, the image is 4.1 cm beneath the lens. What is the focal length of the lens?

    2. Relevant equations
    1/di + 1/do = 1/f

    3. The attempt at a solution
    1/di + 1/do = 1/f
    1/4.1 + 1/12 = 1/f
    f = 3.0559 cm

    What did I do wrong?
  2. jcsd
  3. Apr 3, 2009 #2


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    The image is virtual, so di is considered to be negative.
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