Other contributors have said "The gases used in a light bolb?" is the same question as "Which gases are used in a light bulb?" If you believe that these are not asking the same thing and should be answered differently, click here
In incandescent light bulbs (the regular kind) contain an inert gas, probably Argon. Sometimes there is no gas at all and a vacuum protects the filament. In Florescent bulbs the tubes are filled with...
Argon is sometimes used in incandescent lights. Answer:Fluorescent bulbs contain mercury vapor so do mercury vapor lights, sodium vapor lights contain sodium vapor once they are hot, "neon" lights...