why are the street light in my area yellow??

Question

why not white or any other colour for that matter??

i didn't know what category to put it in, i figure the colour of the light has something to do with how you see so i put it i general science!

Answer 1

They have sodium vapor lamps installed

Answer 2

The emission spectrum of the element Sodium.

One popular design for street lights is the addition of the element Sodium, which is heated to thousands of degrees and forms a plasma. In this plasma, the electrons in Sodium atoms jump into higher orbits. They can't maintain this however, and fall back to their "ground" state. They loose energy in doing so, and this energy is emitted in the form of light waves. The wavelength is directly porportional to the difference in the size of the orbitals the electron traveled. Orbitals have fixed diameters, so all the light is a narrow band of wavelengths. Human eyes interpret them as color, and energized Sodium plasma radiates a yellow orange light. Another common street lamp design uses Mercury plasma. The spectrum of Mercury contains many ultraviolet wavelengths. These are absorbed by a phosphorescent tube and glow white. It is the same fluorescence which ocurrs when some white objects are placed under "black" lights. One problem with Mercury light is it tends to make colors hard to see because of the glare. Street signs are colored, so the softer, yellow light of Sodium lamps are preferred along the street. Mercury lamps are more common in parking lots. If you wear glasses, the blue UV glow of Mercury lamps can be seen just under the bulb.

Answer 3

Because you have sodium vapor lights in your area. Where you add energy to a sodium atom, it gives up the energy by emitting yellow light.

Answer 4

Maybe it is a "bug" light bulb?