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Homework Help: A person can focus objects clearly only between 15 cm and 40 cm.

  1. Oct 29, 2011 #1
    1. The problem statement, all variables and given/known data
    A person can focus objects clearly only between 15 cm and 40 cm. What eyeglasses would you prescribe


    2. Relevant equations
    1/p+1/q=1/f
    P=1/f


    3. The attempt at a solution
    I don't really know what to use for p, or f
     
  2. jcsd
  3. Oct 30, 2011 #2

    rude man

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    Homework Helper
    Gold Member

    Did they teach you about the eye?
    q = distance from eye lens to retina
    p = distance from object viewed to eye lens

    Now think - you want the person to see things at p = infinity but you also want them to focus as close-in as possible, given their innate limitation (uncorrected, p = 15cm to p = 40 cm).
     
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