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Conceptualization of 'real image' formation by concave mirror; other mirror questions

  1. Sep 14, 2012 #1

    I realize that this might be kind of a silly question, but I am in a physics class currently and I'm having the hardest time visualizing what exactly is happening when a 'real image' is formed on the same side as the object (as in the case of an object emitting light on the concave side of a curved mirror). What is a person viewing from the object's vantage point seeing in this case? (Are they seeing a projection of the image on their side of the mirror? Or just a point of light?)

    I also had a question regarding multiple reflections using two mirrors; namely, if two mirrors are placed at some angle smaller than 90 degrees along one axis to one another, a person standing in between the two planar mirrors would be able to see more than one reflection of him/herself, correct?

    If this is true:

    1) How can one determine the number of images based on the angle?

    2) How would this change if the two mirrors were convex or concave? How would it change if another mirror were placed behind the person (enclosing them within an equilateral triangle)?

    Thank you in advance for any help! I would very much appreciate hearing back from anyone on this matter. :)
  2. jcsd
  3. Sep 14, 2012 #2

    Simon Bridge

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    Re: Conceptualization of 'real image' formation by concave mirror; other mirror quest

    Welcome to PF;
    It is difficult to see when you only have the little mirrors commonly used in class. Basically, the real image just looks like the object is actually sitting there. When you see it with a very big mirror the illusion is startling: if you are the object, what you see is yourself hanging upside down in space in front of you. You can even reach out and "touch" the image of yourself (since there is nothing there, your hand passes through the image ...)

    Normally the "image" is in the same place as the "object" - that is how your visual system locates objects. It is only when we mess about with mirrors and bits of glass that the distinction becomes important.

    What happens with multiple mirrors is that you see the reflection of one mirror in another one ... the image from one mirror acts as an object for the other one. You can work out the rules experimentally or with ray diagrams. Since this is a common exercize for beginning students I won't spoil it for you now ;)
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