Incandescent light bulb Small variations in resistivity along the filament cause "hot spots" to form at points of higher resistivity; a variation of diameter of only 1% will cause a 25% reduction in service life. These hot spots evaporate faster than the rest of the filament, which increases the resistance at that point—this creates a positive feedback that ends in the familiar tiny gap in an otherwise healthy-looking filament. Irving Langmuir found that an inert gas, instead of vacuum, would retard evaporation. General service incandescent light bulbs over about 25 watts in rating are now filled with a mixture of mostly argon and
Longest-lasting light bulbs down in 1937, but the bulb's power was supposedly uninterrupted, according to General Electric, and the bulb continued to burn while a second tower was constructed. However, according to museum curator Jack Stanley, the bulb is fake, consisting of a hollow bulb illuminated by a series of automobile headlights mounted in the display's base. Longest-lasting light bulbs This is a list of the longest-lasting incandescent light bulbs. The world's longest-lasting light bulb is the Centennial Light located at 4550 East Avenue, Livermore, California. It is maintained by the Livermore-Pleasanton Fire Department. The fire department claims that the bulb is at