olemus
ruumis lainena leviv elektromagnetvälja olekumuutus:
- välja elektriline komponent ja magnetiline komponent võnguvad teineteise suhtes ja laine levimissuuna suhtes risti, olles samas faasis

täpsemalt
http://www.mpoweruk.com/radio.htm

http://pages.mtu.edu/~scarn/teaching/GE4250/EM_theory_lecture.pdf

https://www.intechopen.com/books/electromagnetic-radiation

spekter

http://www.mpoweruk.com/images/emspectrum.gif

https://defendershield.com/wp-content/uploads/electromagnetic-spectrum-diagram.png

https://churchofthecosmos.files.wordpress.com/2012/12/electromagnetic-spectrum.png%3Fw%3D455%26h%3D276

https://www.youtube.com/watch?v=cfXzwh3KadE

http://www.physics-and-radio-electronics.com/physics/electromagnetic-spectrum.html

http://irina.eas.gatech.edu/EAS_Fall2008/Lecture1.pdf

http://physics.info/em-spectrum/