Which kind of street light bulb rated at the same wattage gives off more light? Mercury or sodium? How come?
Sodium and neon as aspects have not got an identical digital shape, no longer only in terms of style of electrons, however the capability stages at which the orbitals lie. while mild is given off by using a lamp, what you're seeing is the emission of capability which the electrons interior the atoms had adsorbed to circulate as much as bigger capability orbitals from decrease ones. because of fact the adaptation in those stages is distinctive in neon and sodium, the wavelength of the sunshine emitted would be distinctive.
Well thats a good question. If you are talking about efficiency, low-pressure sodium (LPS) lamps give the most output power for the input power. And that is why they are used. HID lamps are all very efficient, but LPS gives out 200 lumens/W. The brightness mainly has to do with thier output at the most sensistive color range of human eyes. High-pressure sodium (HPS) gives better color output at the cost of a loss of efficiency. Metal halide lamps give much better color than all other HID classes, hence thier use in stadiums. They have the best quality light/efficiency combo.
The most efficient light, in terms of lumens per watt, is low-pressure sodium. Because these give light almost exclusively from the sodium D-lines (589 nm), they do not do well at showing colors and are used mostly in areas where light pollution of nearby astronomical observatories is to be minimzed (as near the Carlsbad observatory on the southern California coast). Next best are high-pressure sodium lamps, which give a yellowish light that has enough spectral components other than sodium-D to gove much better color renditiion. Next best is mercury vapor, but these give only about half as much light as high-pressure sodium, so they are being phased out of streetlight service. Trailing far behind are incandescent lamps, which used to be common but are now rare.
