2 A B C D E F G H I K L M N O P R S T U V W


Light that we can see (“visible light”, “VIS”) is a small part of a spectrum of a thing called “electromagnetic radiation”, distinguished by something we call “wavelength”.
As the wavelength varies in the visible spectrum, the light appearantly changes color from violet to red.

image of Frauhofer-Lines

There are no actual boundaries between one range of wavelengths and another. So numbers associated with a certain range are only approximate.

If we explore the spectrum from long wavelengths to shorter wavelengths, we meet :

  • “radio waves” : regular broadcast wavelengths are for example 500 meters long, but even longer radio waves exist
  • “short waves” :  (“Radar waves”, “Millimeter waves”)
  • “infrared”
  • “visible light”
  • “ultraviolet light”
  • soft x-rays
  • x-rays
  • hard x-rays
  • gamma rays

BuildingsHumansButterfliesNeedle PointProtozoansMoleculesAtomsAtomic Nuclei104108101210151016101810201 K100 K10,000 K10,000,000 KPenetrates Earth'sAtmosphere?RadioMicrowaveInfraredVisibleUltravioletX-rayGamma ray10310−210−50.5×10−610−810−1010−12Radiation TypeWavelength (m)Approximate Scaleof WavelengthFrequency (Hz)Temperature ofobjects at which this radiation is themost intensewavelength emitted−272 °C−173 °C9,727 °C~10,000,000 °C
(C) Wikipedia, file : https://upload.wikimedia.org/wikipedia/commons/c/cf/EM_Spectrum_Properties_edit.svg