I'm having a bit of trouble understanding Balmer lines, is this correct, and the questions are in brackets:
1) A star needs to be hot enough such that electrons are in the n=2 state (why does the temperature cause the electrons to be in n=2 state?)
2)As light of a specific frequency passes through the star's atmosphere it excites these electrons in the n=2 state raising them to higher energy levels (why can't it excite electrons not in n=2?)
3) The electrons the de-excite and drop back down to n=2 (why can't say and electron originally in n=3, drop down to n=2 without being excited in point 2)
4) The lose of energy is emitted as photons (E=hf) in random directions, and possibly in multiple steps (what is the correct phrasing for this, I mean perhaps two photons will be emitted from n=4 to n=3 to n=2 and so won't be the same frequency as the specific frequency in point 2 which correlates to Balmer lines)
5) this results in reduced intensity at the specific that correlate to Balmer absorption lines.