An incandescent bulb, made of a wire filament encased in glass, emits only 5% of the energy it consumes as light; the rest is wasted as heat.
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Related: filament
Prev: When a silver filament reaches the gold, it forms a short circuit, causing a dramatic change in conductance, which is easily detectable.
Next: Think about a light bulb; if you apply a current, the filament gets hot and begins to give off light of different colors - red then yellow then blue.
