How does a filament bulb produce light?

Answer 1

Everything above absolute zero gives off radiation. We can only see a small fraction of that radiation. Some snakes see heat that we can see only with special equipment. Some insects see ultraviolet which we also need special equipment to see. We see the radiation in the colors that the sun gives off. At night we see very little. If something is heated hot enough, it gives off radiation close to the color that the sun gives off. You can see that when you look at a gas stove. You can see the hottest blue flame then a cooler yellow flame and then a cooler red flame. If you run electricity through some substances, you will heat them up until they give off heat or light. Thus, with certain materials you can heat a filament until it reaches the temperature where it gives off a white light. The filament is enclosed in glass to keep out oxygen. Otherwise the filament would burn up. So a filament gets real hot like a stove and then gives off light.

Florescent lights do not need to get nearly near as hot and use far less electricity. Soon there will be diode bulbs that use even less.

Answer 2

Fluorescent lights are quite different from regular incandescents. Incandescents have a filament the glows white hot, producing light. Fluorescents, on the other hand, are more like neon lights: electricity is used to excite a gas to produce light. Unlike neon lights, the light produced by the gas is ultraviolet. The ultraviolet radiation strikes a white "phosphor" (though not necessarily made with the element phosphorus) coating on the inside of the tube, which then emits the visible light we see.

Be careful handling any broken fluorescent tubes: the gas used to produce the ultraviolet contains Mercury, which is a neurotoxin, and the phosphor is a powder that is easily inhaled. None are good for your health!

For more detail on the circuitry, why some have starters/start buttons, etc. see the information in the Related Links shown below.

Answer 3

A fluorescent lamp is a glass tube containg some mercury vapor, with a phosphorescent coating on the interior surface of the tube.

The mercury vapor is made to glow by using a high voltage across its electrodes that sets off an electric arc discharge in the tube. The discharge can also be described as a conducting plasma.

The resulting flow of current through the mercury vapor is stable and well-controlled by an external ballast, or loading device, which consists of a high-inductance choke coil wire in series with the tube.

The continuing dischange glow is invisible to the human eye but it causes the phosphorescent coating on the interior surface of the tube to emit visible light.

For more information see the Related link below and the answers to the Related Questions.

Answer 4

A fluorescent light bulb contains a low pressure mercury vapor gas-discharge lamp. This lamp produces visible light by sending electrical current through the mercury vapor and energizing the molecules. This produces ultraviolet light that causes a phosphor coating on the bulb to glow.

Answer 5

Everything above absolute zero gives off radiation. We can only see a small fraction of that radiation. Some snakes see heat that we can see only with special equipment. Some insects see ultraviolet which we also need special equipment to see. We see the radiation in the colors that the sun gives off. At night we see very little. If something is heated hot enough, it gives off radiation close to the color that the sun gives off. You can see that when you look at a gas stove. You can see the hottest blue flame then a cooler yellow flame and then a cooler red flame. If you run electricity through some substances, you will heat them up until they give off heat or light. Thus, with certain materials you can heat a filament until it reaches the temperature where it gives off a white light. The filament is enclosed in glass to keep out oxygen. Otherwise the filament would burn up. So a filament gets real hot like a stove and then gives off light.

Florescent lights do not need to get nearly near as hot and use far less electricity. Soon there will be diode bulbs that use even less.

Answer 6

An electric current flows through the filament which is usually made of tungsten because its melting point is the highest of all metals. The filament heats to around 3000 degrees C and becomes incandescent, radiating heat and light by what is technically called black body radiation.

Answer 7

when the coil wire in the bulb has electricity passing through it the wire heats up to then create light.

Answer 8

the part in the light bulb that produces the light.

Answer 9

Check the link for a good treatment of the subject.

Answer 10

A current passes through the filament. Part of the electrical energy passing through gets converted into heat, making the filament so hot that it glows.