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UV Light and metal (Tech stuff)


#1

G’day; there is no metal that gives off more UV than any other at a
given temperature. The UV radiation comes from the temperature of
any highly heated object no matter what it is so long as it doesn’t
change because of heat… At room temperature no UV is radiated; UV
is negligible at temperatures lower than white heat. UV is
considerable and thus dangerous at such high temperatures as the sun,
a welding arc, a carbon arc lamp or a bomb.

The spectrum of electro magnetic radiation radiation is very wide
indeed. Even at a degree above absolute zero (-230C) an object
still radiates at some very long wavelength indeed. Infra red is
easily detected at 35C; All mammals radiate infra red. An electric
soldering iron radiates infra red strongly and at 500C human nerves
detect it very easily at well over a foot distant. At 650C the object
is only just detectable by the human eye in an otherwise totally
dark room, as a very dark, dull red. At 1150C - molten steel - you
see it glowing as white hot. As soon as you get to around 1000C
invisible Ultra violet enters into the equation. At 2000C the object
is so hot as to be positively dazzling and it is just below that
temperature that platinum melts. So hot that you can’t look at it
and must have dark glasses to view it. But most glasses are fairly
transparent to UV, and such glasses need a component that blocks UV.
Go even hotter and you get long wavelength radio. An arc will
radiate plenty of radio interference. A fluorescent tube light gives
off some radio, unless properly designed. (it is an arc too, and is
called a plasma) Finally fission or fusion bombs give off enormous
pulses of radiation at a very huge range of wavelengths indeed, from
harmless infra red right up to and including x-rays. Which is why a
fusion bomb set off in orbit will destroy radio transmitters; it is
so powerful. An atomic bomb explosion produces an enormous pulse of
electricity which will induce a high electric current in conductors,
sufficient to burn them out. So will lightening, of course.

So, at silver soldering temperatures, practically no ultra violet
radiation is given off at all. But plenty of infra red is given off,
and prolonged exposure to strong infra red, such as from orange hot
molten glass will affect eyesight. – Cheers for now,

John Burgess; @John_Burgess2 of Mapua, Nelson NZ