Light and the spectrum.

[lndm]

Does anyone know whether visible light is actually a part of the electromagnetic spectrum? Is it perhaps a photon discharge instead?

[pinkmouse]

Light is a part of the EM spectrum. An elegant demonstration of this can be seen by the cosmic background radiation, light that is so Doppler shifted that it appears as microwaves. However, on smaller scales, light does also exhibit particle like qualities, and these are called photons. This whole aspect is known as wave/particle duality, and I'm sure a google search will give you more info than you ever wanted. A particularly good example is the two slit experiment.

[lndm]

Both? I thought I'd not heard a straight answer before!

I can surmise from the two slit experiment that the null patterns suggest wave like behaviour, and the fact that light intensity responds to temperature, for one thing suggests it has mass.

Thanks Pinkmouse.

[SY]

Light intensity is just number of photons per second. Light energy per photon is directly proportional to frequency.

And to make things worse, all electromagnetic interaction, even simple Coulombic attraction/repulsion, is mediated by exchanges of photons...

[lndm]

Coloumb. Isn't he that guy that said one Coloumb per second equals one Amp? It sounds as if you're talking about electrons in a conductor, but this isn't EMI is it? Maybe you're saying that antenna interactions are subject to photon like behaviour?

[SY]

Any electromagnetic interaction, whether RF, light, magnets attracting or repelling, charges attracting or repelling, infrared radiation, whatever, is an exchange of photons.

[lndm]

You learn something every day. I had my head in RF gear. It's easy to forget that magnetism goes down to DC.

That reminds me, I recently took delivery of some neodymium/iron/boron magnets. Very cool, good for party tricks.

I think I wanted to do something with ribbons. I'm a bit worried it will take more of my time than I have right now. Hmm, it would be nice.

[Curmudgeon]

Succinct and excellent answers; a general acknowledgement of light's being a portion of the electromagnetic spectrum is the characterization of a broadband amplifier as being flat from DC to daylight .

A spectral chart is fun; shows ELF waves up through microwave, infra red, visible, UV, X-Rays out to hard gamma rays.

[KBK]

Originally posted by SY


And to make things worse, all electromagnetic interaction, even simple Coulombic attraction/repulsion, is mediated by exchanges of photons...

Tanks sigh. I had no idea. Additional clarity. hhhmmm ...angluar components/resultants of field stressing.

Did you ever take a a look at the 'compleat' Maxwell's equations which are now published on the net? The complete quarternion version, instead of Heavside's simplified version for engineering idiots? You know, the original-the one that mathematically allows for what we speculatively call 'over-unity', simply because we have been denied the math..which oddy enough....has been in existence for well over 100 years. Gotta love those self important types, who modify a man's work, after he dies. And ruin it in the process.

[SY]

I never studied the Heaviside version, just the stuff in Jackson (shudder!). I don't think we needed quaternians.