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Homework Help: Difference between convex lens formula and convex mirror formula

  1. Aug 4, 2011 #1
    1. The problem statement, all variables and given/known data

    difference between convex lens formula and convex mirror formula




    3. The attempt at a solution

    for convex mirror you make focal point negative and use the 1/f = 1/do + 1/di

    but for convex lens do you do the same?

    you don't make the f negative i think am i right?

    thank you
     
  2. jcsd
  3. Aug 4, 2011 #2
    Correct. So for the record, the sign convention for f is:
    Positive: Concave mirror, convex lens
    Negative: Convex mirror, concave lens
     
  4. Aug 4, 2011 #3
    thank you
     
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