Ultraviolet (UV) rays are an invisible component of solar radiation to the human eye.
The visible spectrum (also called optical) represents the field of the electromagnetic spectrum that is visible and can be detected by the human eye without any aids. Electromagnetic radiation in this wavelength range is called (visible) light. Under normal conditions, the human eye perceives in the air the wavelengths in the range of 380 - 750 nm nanometers with a frequency of 430 THz (750 nm) up to 750 THz (380 nm).
UV solar radiation is of 3 categories:
- UV-A (315-400nm)
- UV-B (280-315 nm)
- UV-C (100-280nm)
UVA and UVB radiation reach the earth's surface and are the radiations that cause skin aging (UVA) and serious skin burns (UVB).
UVC rays are blocked by the earth's atmosphere, and these are the only UV rays that have a disinfecting effect, because they affect the DNA structures of microorganisms, and they can no longer multiply, so they cannot infect.
What is the electromagnetic spectrum?
The electromagnetic spectrum represents the totality of wavelengths or frequencies of electromagnetic radiation existing in the universe.
There is more than meets the eye!
Introduction to the electromagnetic spectrum:
References:
https://science.nasa.gov/ems/
https://uihc.org/health-topics/what-difference-between-uva-and-uvb-rays
https://ro.wikipedia.org/