- I understand when the current flows through the lamp, the electrons collide with the mercury atom and causes them to be ionised. But how does this work? In terms of the energy transfer between energy levels?
I think I vaguely understand how it works but not completely. So far, I understand that fluorescent lamps have an electrode at both ends and are filled with an unreactive, low-pressure gas such as mercury. When the current passes through, the electrons are accelerated and they collide with the mercury atoms and causes them to be ionised. (But how are they ionised here?) I also understand that when the electron collides with the mercury atom, it can knock an electron out and thus causing it to be ionised. If the electron came from a lower energy level, an electron falls from a higher level to fill this gap causing the emission of a photon. However, when does the electron move to a higher energy level? How will the photon be emitted here?