Is it possible to save the light? I am just thinking why can't we save the light (not a bulb). Lights normally get reflect by mirror, when source is off reflection is gone or absorbed or discharged by other object in room. 
Can't we save light, if we create the the closed square box using reflection mirrors with tiny hole. I am thinking to use the tiny hole as light source. If we turn on and off the source mirrors start reflecting the light infinity right? 
If no, can someone tell me why can't!
If yes, I can't think where it will applicable, because we can't live in mirror box! Just that question hits my mind :P
 A: Yes, it is possible to "store light" and was experimentaly demonstrated a decade ago by M. D. Lukin et. al.
The research is still on. Search "slow light" or "stop light" for more material.
here is a link to the relevant paper- 
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.86.783
here Lukin explains the phenomena -
https://www.youtube.com/watch?v=V65IGIKXsVQ
more explanatory videos are available at YouTube.
A: You can't save it forever.  The light would slowly destroy the box to the point where the energy would leak out.  For every action there is an equal and opposite reaction and the only thing to push back when the light reflects is the structural integrity of the container.  So at some point, the mirror would be too weak to reflect it, and would allow the light to escape.
Another alternative would be that instead of the container getting weak, the light would get strong.  Light can align itself by being continually reflected in a consistent pattern.  Given the opportunity to interfere with itself the light can become organized in a way that is called a 'coherent' beam and apply all of its energy more efficiently.  Then it would escape as a single ray through the first weak point in the mirroring, and you would be making a LASER.
I don't see why we can't live in a mirrored box.  Freeman Dyson proposed this would be an excellent way of optimizing our use of the sun for the long term: https://en.wikipedia.org/wiki/Dyson_sphere.
