So today I was asked a question which I found very simple yet I honestly couldn't explain (embarrassingly).
One of my mum's friends who knows I'm a scientist asked me "If I turn the light off in a room why does the light instantly disappear"
To phrase it up in a more scientific way :
If we took a box of light and sealed up the entrance to the box such that the photons can't escape, how come (since the photons are still inside the box) it appears dark?
My thoughts were to do with the source of the radiation being removed, but I have no idea why photons bouncing about inside the box do not light up the inside? Intensity maybe?
I guess its sort of like black body radiation approximated by a cavity with radiation inside and a pin small hole following Planck's model, but in this case we just close the hole rather than measure any emitted radiation.
Edit Thank you all very much for your answers! I understand now. Hypothetically speaking if the walls were of a material that did not permit the adsorption of a certain frequency of the light would it just bounce around forever? (I actually have another "simple" question to ask, but I will ask it in a separate part later this evening. Thanks again :)