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Homework Help: Help! Geometric Objects Thin lenses Problem

  1. Dec 6, 2012 #1
    I really need help with this problem. Give me at least a hint on how to solve it.

    You are standing in front of a lens that projects an image of you onto a wall 2.00m on the other side of the lens. This image is three times your height.

    How far are you from the lens?

    What is the focal length of the lens?

    Your help will be much appreciated :'0
  2. jcsd
  3. Dec 6, 2012 #2
    Have you learnt:
    (i) The relationship between image size and object size?
    (ii) The relationship between image distance, object distance and focal length for a thin lens?

    If not, I recommend you review your notes/textbook.
  4. Dec 7, 2012 #3
    The problem tells you what the magnification is.
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