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Light in a perfect reflective box

  1. Oct 5, 2009 #1
    Hi guys i thought i've seen a thread on this before but i was wondering, supposingly you have a black box which is totally airtight and made in such a way nothing, not even an atom is capable of escaping from the box.

    This box is also 100% reflective on all sides and in the middle of the box there is a bulb which lits up. Since the box is 100% reflective, would the light collected from the emission of the bulb eventually cause the box to "blow" up or rather, gets super bright over time? Thanks for any reply i was trying to explain the phenomenon of light particles to a junior.
  2. jcsd
  3. Oct 5, 2009 #2

    Andy Resnick

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    The interior of the box would continue to heat up as long as current is supplied to the bulb.
  4. Oct 5, 2009 #3


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    A light bulb not only emits but also absorbs energy. At some point the energy density will be so great that the light bulb will absorb as much as it emits. The amount of energy in the box will stay constant from then on.

    Blow up the box? If it is 100% reflective it will not melt, but the reflected photons exert a force in the walls. So yes, in theory you might blow up a box with captured light alone. But 100% reflective materials don't exist.
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