Ultraviolet (UV) aka "Blacklight"

0.75 - 30 PHz 400 - 10 nm
UV-A (380-315 nm), UV-B (315-280 nm), and UV-C (280-10 nm)
UV lies just above the visible spectrum, hence ultra violet (beyond violet). It's mostly know for the responsable wave for a brown tan.

Effects:

UV-A tans you, while UV-B burns the skin. Health concerns are mostly in this region, although lower regions can have other health concerns.

Sources:

Stars, Sun, BB, Heat

Uses:

Solar cel (zonnecel), photolithography (a.o. in making microchips), spectroscopy
Washing powders (to look 'whiter' due to fluorescent dyes)
Analysis of minerals, detective work
Astronomy (which radiation doesn't this use ?)
UV-A: Blacklights (fluorescent lamps), skin tanning, skin therapy
UV-C: Disinfection/Sterilization (air, water, surfaces)

Interaction with matter:

Effects:

makes bees "see" interesting flowers
Besides tanning (which is the result of brown pigment melaninon which itself blocks UV as a defense), the upper ranges are unhealthy for our skin (UV-B, UV-C) and can produce skin cancer (UV-B)
UV-B (and UV-C somewhat) can destroy DNA if it can reach it.
Germicidal ultraviolet (UV-C / 253.7 nm): kills germs, such as bacteria, viruses, mold, fungi and spores
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