2007-05-02 04:00:07 · 7 answers · asked by Christine 1 in Science & Mathematics ➔ Physics
Most light bulbs are white, because they are just emitting blackbody radiation meant to imitate the sun (which is what our eyeballs evolved to see best). Yours probably has some sodium in it, which has resonances in yellow frequencies. Mercury lights are bluish for the same reason. You can also make decorative lights of any color you choose just by putting colored glass on the outside.
2007-05-02 04:02:58 · answer #1 · answered by Anonymous · 1⤊ 1⤋
Sorry to contradict you but I have seen many bulbs of other colors. These colored bulbs are used as night lamps and for decorative purpose. Normal Incandescent lamps are clear and the light is slightly yellowish because of the temperature of the tungsten filament. Flourescent tubes on the other hand emit a light of temperature about 6000 to 6500 K corresponding to the surface temperature of the sun.
The light from a mercury vapor lamp is always golden yellow since the emission lines (spectrum) of sodium atoms is in the yellow region of visible light.
2007-05-02 11:06:16 · answer #2 · answered by Swamy 7 · 1⤊ 0⤋
An incandescent bulb is usually about 3200k.
A flourescent will put out anywhere from 2700k-6500k (think pink to blue in the color spectrum).
A big portion as to why a regular light bulb (an incandescent) is usually yellow is based on how it's made. An incandescent has a filament as opposed to igniting due to gas (that gas is mercury, which is found in flourescent and compact flourescent bulbs).
2007-05-04 19:18:08 · answer #3 · answered by ladysecretz 4 · 0⤊ 0⤋
“Always yellow?” That’s pretty darned exclusive, and definitely not true. I have Christmas lighting that comes in all sorts of colors like red, green, blue, white, etc. I have a “bug light” that is distinctly yellow; a darkroom safe-light that is a deep, deep, red; and an ultra-violet light that you can barely see glowing. All of these are ordinary incandescent lamps with tungsten filaments.
It is true that, at the operating temperature of an incandescent lamp, there is a distinctly yellowish cast to the emitted light, but that is a simple consequence of the wavelength distribution of blackbody radiation emitted from any source at the operating temperature of a tungsten filament lamp. The actual wavelength distribution is continuous from the infrared through the visible and into the ultraviolet as you can verify with a prism. The peak of this distribution happens to coincide with the color we perceive as yellow, but all the other colors are there too. And that is why incandescent lamps can be filtered to select one color (or range of colors) from the entire spectrum of colors.
2007-05-02 11:16:36 · answer #4 · answered by hevans1944 5 · 1⤊ 0⤋
We all seem a bit mixed up here! The sun is a yellowish colour because of its temperature, and we evolved to make use of that, which is probably why we use light bulbs at a similar temperature and hence spectrum, talking old-fashioned incandescent lamps now. A mercury vapour lamp, in my experience, is not at all yellow, though a sodium lamp certainly is. The mercury tubes we used in labs (eons ago) were more of a bluish colour.
2007-05-02 11:12:36 · answer #5 · answered by Diana 2 · 0⤊ 0⤋
its not always...it just doesnt have many bolts in it compared to a white light bulb.
Just like the sun is a yellow-orange-red color adn there are other stars that are white...the sun has a shorter life left than those brighter stars
2007-05-02 11:12:17 · answer #6 · answered by Kim 3 · 0⤊ 1⤋
It is not always yellow. There are white, cool-white and soft white, and also pink bulbs; and clear.
2007-05-02 11:07:43 · answer #7 · answered by hopflower 7 · 0⤊ 0⤋