What temperature must an incandescent filament be heated to in order to glow?

An incandescent filament must reach a temperature of approximately 5000°F to produce visible light. At this high temperature, the filament exhibits incandescence, which is the emission of light due to its thermal energy. The glowing effect occurs as the filament heats up to a point where it emits photons in the visible spectrum, making it glow brightly.

Temperatures below this threshold would typically not produce sufficient thermal energy for the filament to emit visible light. While temperatures higher than 5000°F might be theoretically reached by some materials, common incandescent bulbs designed to emit light generally operate effectively around the 5000°F mark. This temperature is a standard reference for incandescent bulbs, as it represents a balance between light output and filament longevity.