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Homework Help: Mirror Equation?

  1. Mar 13, 2014 #1
    1. The problem statement, all variables and given/known data

    An ant is 1.03 cm tall and stands 4.90 cm in front of an unknown mirror. To its surprise the ant sees an its image which is 4.43 cm tall! What is the the distance to the image? What is the focal length of the mirror?

    2. Relevant equations

    The mirror equation: 1/p + 1/q = 1/f

    p: object distance
    q: image distance
    f: focal length

    Maybe the magnification equation?: M = -q/p = h'/h

    q: image distance
    p: object distance
    h': image height
    h: object height

    3. The attempt at a solution

    I set the problem up this way:

    1/4.90 + 1/q = 1/f

    I have no idea how to figure it out beyond this point.

    Please help! :blushing:
  2. jcsd
  3. Mar 13, 2014 #2


    User Avatar
    Science Advisor
    Homework Helper
    2017 Award

    Try to use the magnification equation... it links p and q.
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