I'm looking at how incandescent light bulbs create light in a more in depth manner, not just "filament gets hot and it glows". I want to know the actual science in an atomic level. I have been researching through books and the internet, and have yet to come to a conclusion whether the light from a tungsten incandescent light bulb comes from: a) The current passing through with a high voltage gives energy to electrons to jump to a higher energy level, and drops back down to ground state, spontaneously emitting photons (visible light). or b) Incandescence, simply due to the high temperature, which meant that the tungsten radiates some visible light instead of only infrared. or c) Both? I am really confused by all these information, some saying it's (a), some say it's (b).