I meant that if there was no decay/spontaneous emission of photons and there was a light beam shining constantly on the blue piece of paper - the blue piece of paper would no longer appear to be blue. All the atoms in the paper would be in an excited state and none of the incoming (red) photons...
Thanks for the info. I was thinking that an atom in an excited state might spontaneously decay due to quantum uncertainty.
For a more of a specific example though - I was wondering what happens, say, for example when a light beam hits a blue sheet of paper. The red end of the spectrum is...
I understand that a photon can be 'absorbed' by an electron resulting in the electron jumping to a higher energy level within an atom. I also understand that a photon is emitted when an electron jumps to a lower energy level within an atom.
But why does the electron jump to a lower energy...