Question

Which gas is filled in an electric bulb and why? Why is tungsten used in the filament of lamps?

Answer 1

Electric bulb:

1. Argon is a gas that is commonly used to fill incandescent light bulbs.
2. It extends the life of the bulb by preventing the tungsten filament from deteriorating too quickly.
3. Other gases used in lightning include helium, neon nitrogen, and krypton.

Use of Ar gas in bulb:

1. In fluorescent and incandescent light bulbs, argon gas is used to prevent oxygen from corroding the hot tungsten filament.
2. The use of argon in light bulbs prevents tungsten filament evaporation, resulting in longer light bulb life.
3. Argon is also used to create an inert atmosphere for semiconductor crystal growth, arc welding, and other processes that require protection from other atmospheric gases.

Tungsten in the filament:

1. Tungsten is used in electric bulbs because it has a high melting point and it does not oxidize.
2. Thus tungsten filament does not melt even when a large amount of heat is produced due to the passage of current through the filament (via the heating effect of current).