Question

The importance of glass enclosure in incandescent bulb is

• A. to preserve and protect the filament from evaporating.
• B. to preserve and protect the filament from extra heating.
• C. to preserve and protect the filament from cooling.
• D. to preserve the temperature around the filament.

Answer 1

The correct option is A

to preserve and protect the filament from evaporating.

An incandescent bulb typically consists of a glass enclosure containing a tungsten filament. Incandescent light bulbs usually contain a stem or glass mount attached to the bulb's base which allows the electrical contacts to run through the envelope without gas/air leaks. Small wires embedded in the stem support the filament and/or its lead wires. The main reason of having glass enclosure is that it contains either a vacuum or an inert gas to preserve and protect the filament from evaporating. This leads to breaking of filament i.e. circuit breaking.