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Homework Help: Two Converging Lense Questions Please Help

  1. May 8, 2003 #1
    For a lens of focal length f, what value of the distance between the object and the lens[D0] would give an image with a magnification of one?

    Is it possible to obtain a non-inverted image with a converging spherical lens? Explain please?

    Any response would be greatly appreciated, and I would like to thank anyone for their response to this thread in advance.
  2. jcsd
  3. May 8, 2003 #2
    Hi JM2107,
    to answer questions like this, you could use use 2 methods:
    1) Draw 3 rays, remembering that...
    ... focal ray becomes parallel ray
    ... parallel ray becomes focal ray
    ... central ray is not refracted
    2) Use the Law of lenses: 1/o + 1/i = 1/f
    o = distance of object from lens
    i = distance of image from lens
    f = focal length

    Got it? :wink:
  4. May 8, 2003 #3

    Claude Bile

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    Science Advisor

    It is not possible to obtain a non inverted image using a single converging lens. It is therefore not possible to obtain a magnification of 1, though it is possible to obtain a magnification of -1. (Inverted images have a negative magnification by convention).

    The reason for this is purely geometrical. Arcnets outlined a standard graphical method of seeing why this is.
  5. May 9, 2003 #4
    R u sure? How about a virtual image? See here...

    Last edited by a moderator: Apr 20, 2017
  6. May 9, 2003 #5
    Here's the answer:

    Yes, it is possible to obtain a non-inverted image with a converging lens. As long as the object is between the focal length point and the lens it is possible. Of course this would be a virtual image and the image would be magnified.


    If m=1 than we have an equation where we can put d (object) = - d (image). Since 1/f = 1/d (object) + 1/d (image) and since d (object) = - d (image), therefore 1/f = 0

    So there is no distance that would give a magnification of one.
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