Hi, My Question Is taht where does light go when we switched off the Source of light.
Is it in theory possible to create a closed room with highly reflecting, non-absorbing materials so that the light isn't lost? would this room stay bright? If so, I guess the viewer would absorb the light eventually in the process of observing the room.
"Highly" reflecting is not enough, it has to be perfect. The walls would have to be perfect crystals of infinite size. But sure, playing on crystal perfection and size, you can tune how long the light will stay inside. Well, at least one wavelength and its harmonics.