I am submitting this question because I am confused on how light is absorbed and emitted from atoms and how that relates to the colours we see. I have tried reaseaching the answer to my question but haven't had a solid answer. So I decided to ask on this forum.
So my question goes like this:
If I was to passed an electric current though a material with atoms that have electrons that absorb some engery equal to the energy difference between the energy levels then that electron would jump to the next energy level but only stay there very briefly and fall back down to its original energy level emitting a photon with the same amount of energy that was absorbed. And since the energy of a photon is directly proportional to the wavelength of that photon, the material would only emited certain wavelengths of light given by the emission spectrum which may look like this:
So no light is coming in (just electricity) and only certain light is coming out. Those wavelengths of light would then combine to form the colour of that object.
Makes sense so far and I assume this how bulbs work.
Another way to get atoms to emit light is to shine white light on an atom and the electrons would absorb the photon if the energy of that photon was equal to the energy difference between the energy levels. And the electron would jump to the next energy level and be absorbed. All other wavelengths do not have sufficient energy to allow an electron to jump to the next engery level so they will pass though the atom unchanged.
So the absorption spectrum will look like the following:
So light of all wavelengths goes in and only light which is not absorbed comes out.
Now since the electrons fall back down to their original engery level like in the first example, they will emit a photon with the same amount of energy that was absorbed. And since the energy of a photon is directly proportional to the wavelength of that photon, the atom will emit light with wavelengths that are the same as the light which was absorbed.
So you will see all the wavelengths of light be emitted from the atom because the light with insufficient engery passes straight though unchanged and the light which does have enough engery gets re-emitted anyway after it was absorbed. So i'm confused.
Plus none of this reflects what real life objects do because they only emitted the light we see and absorb all other light, not have them pass though unchanged.
Two small other questions:
1). In the first example the electrons moving with current gives energy to the electron in the atom. So the electron in the atom absorbs the moving electron? If so how is this possible because they are both negative?
2). Why is it that the electron loses energy when it jumps to the next energy level?
Someone please explain!