system
Given the following post, respond as if you're commenting on Reddit:
human
What process occurs for a light bulb to be “burnt out”?
gpt
For an incandescent lamp, the tungsten filament evaporates slowly when hot. It is very thin to begin with and parts which are even thinner get hotter and evaporate even faster. Eventually the filament opens because it is just too thin. That often happens when switching the bulb on because the current is much higher for a very brief time. Halogen bulbs slow down the evaporation by redepositing evaporated tungsten onto the filament.