Electromagnetic spectrum: Difference between revisions
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=== Electromagnetic radiation === | === Electromagnetic radiation === | ||
All electromagnetic radiation can be described in terms of its [[Energy]] (E), [[frequency]] (f), [[wavenumber]] (v'), or [[wavelength]] (<math>\lambda</math>). These properties are all related by the following equations: | |||
:<math>\lambda = \frac{c}{f} \,\!</math> , | :<math>\lambda = \frac{c}{f} \,\!</math> , | ||
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where c = 299,792,458 m/s (the [[speed of light]]) and h = 6.626 x 10<sup>-34</sup> Js ([[Planck's constant]]) | where c = 299,792,458 m/s (the [[speed of light]]) and h = 6.626 x 10<sup>-34</sup> Js ([[Planck's constant]]) | ||
As well as the wavelike properties of EM radiation several effects particularly of the emission and absorption of light behave like particles. That is, the energy carried by light waves is packaged in discrete bundles called [[photons]] or [[quanta]]. The particle character of light is described in [[quantum electrodynamics]], a theory which began with Dirac's work of 1927.<ref>P.A.M. Dirac, Proc. Royal Society (London), ''The Quantum Theory of the Emission and Absorption of Radiation'', vol. '''A114'', p. 243 (1927)</ref> | |||
== Reference == | |||
<references /> | |||
==Further reading== | |||
* Young and Freedman. ''University Physics''. Addison-Wesley Publishing Company. ISBN 0-201-31132-1 | * Young and Freedman. ''University Physics''. Addison-Wesley Publishing Company. ISBN 0-201-31132-1 | ||
* [http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html NASA introduction to electromagnetic spectrum] | * [http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html NASA introduction to electromagnetic spectrum] | ||
Revision as of 01:33, 25 August 2008
The Electromagnetic Spectrum is the name given to the range of electromagnetic waves covering all frequencies and wavelengths. It includes radio and television transmission, Microwaves, Infrared, visible light, Ultraviolet, X-rays, and Gamma rays.
Electromagnetic radiation
All electromagnetic radiation can be described in terms of its Energy (E), frequency (f), wavenumber (v'), or wavelength (). These properties are all related by the following equations:
- ,
- ,
where c = 299,792,458 m/s (the speed of light) and h = 6.626 x 10-34 Js (Planck's constant)
As well as the wavelike properties of EM radiation several effects particularly of the emission and absorption of light behave like particles. That is, the energy carried by light waves is packaged in discrete bundles called photons or quanta. The particle character of light is described in quantum electrodynamics, a theory which began with Dirac's work of 1927.[1]
Reference
- ↑ P.A.M. Dirac, Proc. Royal Society (London), The Quantum Theory of the Emission and Absorption of Radiation, vol. 'A114, p. 243 (1927)
Further reading
- Young and Freedman. University Physics. Addison-Wesley Publishing Company. ISBN 0-201-31132-1
- NASA introduction to electromagnetic spectrum