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Mirror on the Wall

  1. May 12, 2007 #1
    If two planes of mirrors (infinite in all directions) were facing each other with nothing in between what would they reflect? How does light come into play in this?
  2. jcsd
  3. May 12, 2007 #2


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    If they were truly infinite in all directions, then the only light between them would be that which was "trapped" when they came into existence.
  4. May 12, 2007 #3
    Answer (whited out)

    As there is nothing in between, there is nothing for them to reflect.
  5. May 13, 2007 #4
    This question is odd, since it is a brain teaser I instinctively thought that there had to be something more to it... but I just can't see what the something could possibly be :/
    Last edited: May 14, 2007
  6. May 14, 2007 #5


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    How hot are the mirrors?
  7. May 14, 2007 #6
    This doesn't seem like a brain teaser to me. It sounds like an optics question. And a pretty basic one at that.

    Mirrors will reflect a certain degree of whatever light is shone at them. So, if there's no light, they'll reflect nothing. If there is light, they'll reflect that light. Depending on the mirror's material, they may not reflect various wavelengths of light (like, say, X-rays or radio waves), but they should certainly reflect most visible light. Eventually, the light will also dissipate, such that nothing as reflected, as each subsequent reflection will decrease the intensity of the light by a certain amount. The amount of dissipation probably depends on the material being used for reflection (usually aluminum in common mirrors), and the specific wavelength of the light. And possibly other factors like ambient temperature, pressure, glass covering, material purity, etc.

  8. May 30, 2007 #7
    But there must be an observer.
  9. May 31, 2007 #8
    There must also be a glass of milk!
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