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Homework Help: Images Formed by converging mirros

  1. Mar 12, 2008 #1
    1. The problem statement, all variables and given/known data

    I need help with this general question. Why is it impossible to focus a virtual image on a screen, ( object is placed between F and lens).

    2. Relevant equations
    this experiment we had a candle on one side, a converging lens in the middle, and at the other end a screen to tell us where the image was formed and how far away from the lens.

    3. The attempt at a solution

    Well, this forms a virtual image right, but how can i measure were the image would be on the screen (paper), is it possible?
  2. jcsd
  3. Mar 12, 2008 #2
  4. Mar 12, 2008 #3
    Well it kinda helps thanks, but my main question is basically can i put a virtual image on a screen ( the image being a candle flame)
  5. Mar 12, 2008 #4
  6. Mar 12, 2008 #5
    This is how I remember the difference between real and virtual images. Since the retina of your eye is a kind of screen, you can imagine yourself, the looker, being a screen. Light enters the eye and you see an object. Where is that object really located? The rays that enter the eye came from a particular direction. Extrapolate those lines back to a point. That point is where it appears to you that the object is located. But did the light really originate from that point, did the light really pass through that point in space? If it did, we call it a real image. If the light never really came from there, it's a virtual image. That's why the image of my face in a flat mirror is a virtual image - because if I take the rays that enter my eye and extrapolate them back, it looks as though the light originated from that imaginary guy who seems to be inside the wall - but i know the light never really passed through that point deep inside the wall. The rule is the same for a curved mirror or for a lens. The question is always: did the light really leave the location where it seems to be coming from? Yes: real image. No: virtual image.
  7. Mar 13, 2008 #6
    Alright thanks guys, helped alot
  8. Mar 13, 2008 #7
    the hyper physics site is amazing
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