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Which gas is commonly used in electric bulbs?
Argon
Oxygen
Nitrogen
Hydrogen
Argon
Argon is an inert noble gas commonly used to fill incandescent electric bulbs. Because it is chemically unreactive, it prevents the tungsten filament from oxidizing and burning out at extremely high operating temperatures.
Argon is an inert noble gas commonly used to fill incandescent electric bulbs. Because it is chemically unreactive, it prevents the tungsten filament from oxidizing and burning out at extremely high operating temperatures.
Think of argon as a protective invisible shield or bodyguard standing around a fragile asset (the tungsten filament) to keep destructive elements like oxygen away.
AR-GON: Always Resisting Glowing Oxidation
P=I2R тАФ Joule's law of heating representing electrical power dissipation in the filament
When an electric current passes through the tungsten filament, it heats up to incandescence due to electrical resistance (P=I2R). In the presence of reactive gases like oxygen, the hot tungsten would instantly oxidize and fail. Filling the bulb with an inert gas like argon reduces the rate of tungsten evaporation and prevents chemical reactions, thereby extending the bulb's working life.
Argon is a noble gas belonging to Group 18 of the periodic table and is chemically inert.
It prevents the oxidation and rapid vaporization of the tungsten filament.
Nitrogen is also sometimes mixed with argon to prevent electrical arcing inside the bulb.
Extends the operational lifespan of the tungsten filament
Reduces bulb blackening caused by tungsten deposition on the glass
Conducts some thermal energy away from the filament, slightly reducing luminous efficiency compared to a theoretical vacuum
Incandescent light bulbs
Fluorescent lighting
Inert shielding gas for arc welding
Argon makes up about 0.93% of Earth's atmosphere, making it the most abundant noble gas in the air.
Option B (Oxygen) supports combustion and would cause the filament to burn out instantly.
A is correct тАФ Argon is an inert gas used to prevent the oxidation of the tungsten filament in electric bulbs.
For railway and technical exams like RRB JE, remember that noble gases are chosen for lighting applications specifically because they do not react chemically with hot metallic filaments.
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