Looking directly at a welder is dangerous because large amounts of UV light is produced. What makes this light? Is it electrons from the current that excites metal atoms, and these atoms sends out UV light? Or does the extreme heat have anything to do with this?
Is it dangerous to look directly at a nail being melted (glowing brightly) by hundreds of amperes?
Is it dangerous looking at an oxyhydrogen explosion in itself, or could it be dangerous if the explosion touches other substances exerting UV light because of the extreme heat of the explosion?
Best Answer
All materials emit thermal radiation (such as light). The hotter the material, the more the radiation is shifted to high frequencies (shorter wavelengths). The radiation comes from oscillating electrons (regardless of whether there is an electric current). Welding reaches temperatures high enough to cause significant emission of UV light. Oxyacetylene and oxyhydrogen flames can both be over 3000 C degrees and therefore can produce hazardous amounts of UV light. Arc welding is even hotter and produces more UV light. Running hundreds of amps of current through a nail would be similar to arc welding.
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