if you were to cover a room completely in mirrors every inch, and say were to turn a flash light on and then off my does it become dark again, why does the light not keep reflecting and bouncing around the room, continually lighting it! im curious as to the scientific reason why? thanks!
-
Every time a mirror reflects light, a small fraction of that light is actually absorbed as well, because no mirror is a perfect mirror in reality, and while that may not matter much at the "everyday" scale, at the "approaching a theoretical infinity" scale it matters a great deal. The light doesn't actually "escape" in this sense, it's absorbed.
This is of course ignoring all quantum effects, which would also matter, and would actually allow some of the light to escape the room. Penetration depth, and quantum tunneling would also play a role here, but honestly, I don't understand them well enough to explain them in a simple yet mostly accurate manner, so I won't even try to do that here, but some of the light actually would escape as well, at least as far as I understand it.
As far as I am aware, the primary contribution to the room going dark would be from the light being absorbed, and not from the quantum effects.
All of this of course assumes that your source of light magically disappears and/or doesn't interact with the light or mirror in any way, and also that there is no detector or that the detector doesn't interact with the light or mirror in any way either (quantum mechanics, yay! Plus a fraction of the light that hits the flashlight or detector would get absorbed). Also, it assumes the mirror covered room is a perfect vacuum (having an atmosphere would mean some of the light gets absorbed every time the light interacts with the molecules, just like what would happen with the mirror basically).
This is of course ignoring all quantum effects, which would also matter, and would actually allow some of the light to escape the room. Penetration depth, and quantum tunneling would also play a role here, but honestly, I don't understand them well enough to explain them in a simple yet mostly accurate manner, so I won't even try to do that here, but some of the light actually would escape as well, at least as far as I understand it.
As far as I am aware, the primary contribution to the room going dark would be from the light being absorbed, and not from the quantum effects.
All of this of course assumes that your source of light magically disappears and/or doesn't interact with the light or mirror in any way, and also that there is no detector or that the detector doesn't interact with the light or mirror in any way either (quantum mechanics, yay! Plus a fraction of the light that hits the flashlight or detector would get absorbed). Also, it assumes the mirror covered room is a perfect vacuum (having an atmosphere would mean some of the light gets absorbed every time the light interacts with the molecules, just like what would happen with the mirror basically).
-
even if you were able to make a mirror that could reflect 100% of optical light, your beam would still dissipate very rapidly for the following reason. light has momentum, when it strikes the mirrored wall it will lose energy and transfer it to the wall. obviously there comes a point when the energy of the light is so low it is no longer in the visible spectra, but you can't make a mirror that is 100% reflective anyway.
-
Light needs to be absorbed by your retina before you can observe it. Even if you had a 100% efficient mirror, the light would still bounce around and never stop, but once you open the door, the light will escape and some of it will hit your eyes, and very soon there will be no light.
-
Even if the mirrors were perfect, the light would be absorbed by you, or the flashlight.
-
Mirrors aren't perfect. Even if they were 99.999% reflective, the light would decay to nothing in a few microseconds because it would lose 0.0001% at each bounce