Can Light Waves Inside an Air-Tight Box be Reduced to Zero?

  • Thread starter xcrunner2414
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In summary, it is possible to build an air-tight box out of 2 inch thick wood, but it will not completely block all forms of light. High frequency electromagnetic waves like X-rays and gamma rays would pass through, and wood is only opaque to visible and near-visible wavelengths. Even if visible light is trapped inside the box, it will eventually dissipate and become close to zero, either through classical or quantum processes. This means that it is not possible to carry light around in a box with you. A more informed answer may provide further details on the behavior of light within a sealed box.
  • #1
xcrunner2414
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If I built a box out of 2 inch thick wood, and made it air tight, would the light waves inside the box eventually dissipate and become absolutely zero? (meaning absolutely no light whatsoever)?
 
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  • #2
Welcome to PF, Xcrunner.
It depends upon how you define 'light'. Anything within the visible spectrum will eventually be depleted, although there might be some tiny spontaneous photon formation. The wood itself will emit infrared based upon its temperature, and higher frequencies such as X-rays won't be blocked.
That's all that I've got; best wait for someone else to provide a better response.
 
  • #3
Hmm. Interesting. I wonder if you put mirrors on the inside surfaces, if you could catch the light and keep it in case the lights go out.

Seriously, though, I'm not sure you could close the box before most of the light got out anyway. Light's sort of a slippery substance. Everything Danger said is true, but... I doubt that you'd catch *any* light to begin with, whether it dissipated or not. Particularly not with 2 inch thick wood... even if it were "air tight".
 
  • #4
Well, unless you sealed it off completely and then had some way to light a match inside or something. Hmm. Who knows? Hopefully you'll get a more informed answer from somebody else...
 
  • #5
I don't mean visible light. I mean the entire light spectrum... x-rays, gamma rays, visible light, infrared, microwaves, etc. all of them as waves. Obviously there are still those waves when I seal up the box, but will the amplitude of those waves every entirely decrease to zero?
 
  • #6
The short answer is 'no'. As mentioned, high-frequency EM won't even notice the walls, and low frequency such as radio will just slide on through as well. Wood is opaque only to visible and near-visible wavelengths.
 
  • #7
For my money, if you catch visible light in a box, it's going to dissipate fairly regularly. In a classical sense, it will probably taper off to zero asymptotically; quantum mechanically, I guess, it may reach a point where (a) it just bounces around forever (no atoms in the wood absorb it because it's the wrong frequency or something) (b) it eventually is all gone (every photon eventually gets absorbed and emitted on the inside of the wood / outside of the box) (c) some crazy thing in between or (d) something completely and qualitatively different than anything I described above.

For my money... signal diminishes to zero, or so close to zero that you may as well assume it's zero. The point being, of course, is you can't carry light around in a box with you (maybe I'm wrong?)
 

1. Can an air-tight box completely block all light waves?

Yes, an air-tight box can completely block all light waves from entering or exiting the box. This is because light waves require a medium to travel through, and an air-tight box provides a barrier that does not allow any medium for the light waves to pass through.

2. Is it possible for light waves to be reduced to zero inside an air-tight box?

Yes, it is possible for light waves to be reduced to zero inside an air-tight box. This can be achieved by blocking all sources of light and ensuring that the box is completely sealed with no gaps for light to enter or exit.

3. What happens to light waves inside an air-tight box?

When an air-tight box is completely sealed, light waves inside the box will continue to bounce around and reflect off the walls of the box. However, without any external sources of light, the intensity of the light waves will decrease over time until they eventually dissipate.

4. Can light waves be trapped inside an air-tight box?

No, light waves cannot be trapped inside an air-tight box. As mentioned before, an air-tight box provides a barrier that does not allow any medium for the light waves to pass through. If there are no sources of light inside the box, the light waves will eventually dissipate.

5. Can the absence of light waves inside an air-tight box affect the temperature inside?

Yes, the absence of light waves inside an air-tight box can affect the temperature inside the box. Light waves carry energy, and without any external sources of light, the temperature inside the box will eventually decrease. This is known as the greenhouse effect, where light waves from the sun are trapped inside a closed space and cause the temperature to increase.

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