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scopethis
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Reged: 05/30/08

Loc: Kingman, Ks
Re: C = 0 new [Re: llanitedave]
      #6009374 - 08/06/13 12:38 PM

if that's the case; when I turn off the light in a room, the area should remain well illuminated....

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ColoHank
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Reged: 06/07/07

Loc: western Colorado
Re: C = 0 new [Re: scopethis]
      #6009437 - 08/06/13 01:01 PM

Quote:

if that's the case; when I turn off the light in a room, the area should remain well illuminated....




Who knows? The room may remain illuminated for another trillionth of a second or so (it depends on the size of room and the texture and color of the walls, etc.) until all of those light photons bouncing around are absorbed and converted to heat energy. I'd attempt to measure it, but my Timex's stopwatch only registers down to 1/100 second.

Edited by ColoHank (08/06/13 01:03 PM)


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Pess
(Title)
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Reged: 09/12/07

Loc: Toledo, Ohio
Re: C = 0 new [Re: ColoHank]
      #6009516 - 08/06/13 01:39 PM

Quote:

Quote:

if that's the case; when I turn off the light in a room, the area should remain well illuminated....




Who knows? The room may remain illuminated for another trillionth of a second or so (it depends on the size of room and the texture and color of the walls, etc.) until all of those light photons bouncing around are absorbed and converted to heat energy. I'd attempt to measure it, but my Timex's stopwatch only registers down to 1/100 second.




Pesse (LOL) Mist


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scopethis
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Reged: 05/30/08

Loc: Kingman, Ks
Re: C = 0 [Re: Pess]
      #6010593 - 08/06/13 11:33 PM

shape the room like a pyramid and line the walls with highly reflective mirrors....ah, the Indian tee pees were so close..

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dickbill
scholastic sledgehammer


Reged: 09/30/08

Re: C = 0 new [Re: scopethis]
      #6015857 - 08/09/13 01:34 PM

hmmm, when you say a photon is absorbed and reemitted, it cannot be reemitted with the same energy, right?
Otherwise it seems to me it'd be a violation of thermodynamic's 2nd law: entropy must increase, some energy must have been lost in the process or it's like there had been no event at all. So i would assume the photons are slightly 'redened' after the event. So a reflected image, for example, should be slighty redened.
That's one thing.

The other thing now is about quantum uncertainty principle. If the absorbtion/reemission is a quantum event, i'd assume that based on this principle, the energy of the reemitted photon should fluctuate a bit, with some reemission events quite far energetically from the absorbtion event in both redened and blued effects. Here the colors of the reflected image should be blurred.

Am i all wrong here?


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llanitedave
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Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: C = 0 new [Re: dickbill]
      #6016045 - 08/09/13 03:07 PM

Entropy doesn't apply to single photons as far as I know, only an aggregate of them. As I understand it, and could be mistaken, reflection efficiency does not affect the wavelength or energy of the photons, but how many are simply not reemitted at all. Those few that are absorbed would go into very slightly heating the mirror.

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dickbill
scholastic sledgehammer


Reged: 09/30/08

Re: C = 0 new [Re: llanitedave]
      #6016143 - 08/09/13 03:56 PM

You make the case that thermodynmic doesn't apply to single event. I am still annoyed by the concept of any event that would occur without an energy difference, but ok.

But what about the quantum uncertainty then? why should the energy of the reemitted photon be exactly the same as the absorbed photon?


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dickbill
scholastic sledgehammer


Reged: 09/30/08

Re: C = 0 new [Re: dickbill]
      #6016152 - 08/09/13 04:03 PM

Oh, i got it, it's dictated by the electronic levels of energy, which are set. So if one electron absorbes one photon and jump one level, it can only go back to the initial level by releasing the same amount of energy.
But why the uncertainty principle doesn't apply, no matter what?


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Carl Coker
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Reged: 07/30/12

Loc: Ohio
Re: C = 0 new [Re: dickbill]
      #6016257 - 08/09/13 05:22 PM

The uncertainty principle does apply, and the energy will almost certainly not be exactly the same. But it will be roughly the same, and which way it changes (and how much) is completely random. Over many events, the re-emitted energy distribution is approximately a Gaussian with a width inversely proportional to the lifetime of the excited state.

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