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Homework Help: Camera Lens Magnification

  1. Mar 24, 2014 #1
    1. The problem statement, all variables and given/known data

    A camera lens has focal length 55mm and an object is 500mm away. Calculate the position of the image and the magnification (or reduction)

    2. Relevant equations

    1/u + 1/v = 1/f

    u = Object Distance

    v = Image Distance

    f = focal length

    m = magnification

    3. The attempt at a solution

    f = 55

    u = 500

    1/500 + 1/v = 1/55

    1/55 - 1/500 = 1/v

    55-1 - 500 -1 = 0.01618

    ANS-1 = 61.79 so approximately 62mm

    v/u = m

    62/500 = 0.124M

    Did I go with the right approach? Any help would be great.
  2. jcsd
  3. Mar 24, 2014 #2
    Looks OK to me.

    The only things I can think of is that the magnification M = -0.124

    1) magnification is supposed to be -ve because the image is usually upside down after the light rays go through a lens provided the object is outside the focal length

    2) 0.124M should just be 0.124 since it is a dimensionless number.
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