- Tungsten filaments operate at very high temperatures (around 2500-3000°C) to produce light by incandescence. - High temperatures cause the tungsten metal to sublime (evaporate) from the filament. - Evaporated tungsten atoms deposit on the cooler glass bulb wall, causing blackening. - Sublimation thins the filament over time, eventually causing it to break. - Inert gases like argon, krypton, or xenon, when present at pressure, impede the movement of tungsten atoms away from the filament, reducing the evaporation rate and thus prolonging the filament's life and preventing rapid blackening of the bulb.
Why is argon gas used along with tungsten wire in an electric bulb?
Asked in UPSC CDS 1 2018 · Topic: Physical Properties of Materials (Thermal Conductivity)
Show answer
Answer: A. To increase the life of the bulb
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