Assuming the question is referring to incandescent light bulbs (the ones with the glowing filament), Argon is the gas used.
Argon is a harmless gas found in air, and is used because it cannot react with the hot filament.
An inert noble gas is used inside light bulbs.
Argon and/or nitrogen.
There are no gasses used in an electric bulb. What's inside is something known as energy. It is known as this because it gives off light. Neon is a gas that is used in light bulbs.
inert gas
Argon
hydrogen is not used in bulbs it is usually argon or another noble gas. e.g neon
Modern bulbs are usually filled with a mixture of argon and nitrogen. More rarely, some bulbs are filled with pure argon, krypton or xenon. The earliest bulbs weren't filled with any gas, but had vacuum inside.
A: There circuitry inside to boost the voltage to 300 500 volts and a triac to conduct the current but the bulbs as opposed to vacuum there is gas inside those coils.
Different kinds of light bulbs used different gasses. The incandescent bulb uses no gas - it uses a vacuum. Other kinds of bulbs may use nitrogen, argon, neon, or krypton.
argon
Modern bulbs are usually filled with a mixture of argon and nitrogen. More rarely, some bulbs are filled with pure argon, krypton or xenon. The earliest bulbs weren't filled with any gas, but had vacuum inside.
They use xenon gas bulbs. These are a form of halogen lighting.