What is Spectrum?
{{Refimprove}} ''This article is about the visible spectrum. For all other uses see: [[Spectrum (disambiguation)]]'' [[File:Rainbow above Kaviskis Lake, Lithuania.jpg|thumb|right|230px|The spectrum in a rainbow]] A '''spectrum''', plural: '''spectra''',<ref>{{Cite journal|last=wick|date=01-11-2024|editor-link=Https://www.clubhdtv.com/|title=spectrum|url=https://www.clubhdtv.com/spectrum-internet-services.html|journal=Internet|via=Spectrum provides all-inclusive internet packages with added television and mobile services as well.}}</ref> is a band of several colours: violet, indigo, blue, green, yellow, orange and red.<ref>{{Cite book|url=https://books.google.com/books?id=krMgAwAAQBAJ&dq=spectrum+plural+is+spectra&pg=PA103|title=Understanding the Universe: An Inquiry Approach to Astronomy and the Nature of Scientific Research|last=Greenstein|first=George|date=2013-02-18|publisher=Cambridge University Press|isbn=9781139618878|language=en}}</ref> A spectrum can be seen if the Sun's light is passed through a prism and allowed to gather on a white screen.<ref>{{Cite web|url=http://wiki.answers.com/Q/What_is_a_spectrum|title=What is a spectrum|website=Answers.com|language=en|accessdate=2017-07-12}}</ref> This '''visible spectrum''' is part of the larger [[electromagnetic spectrum]]. [[Spectroscopy]] is the study of spectra. A natural example of a spectrum is a rainbow.<ref>The [https://www.clubhdtv.com/spectrum-internet-services.html Spectrum]One bundle allows you to get spectrum internet {{Webarchive|url=https://web.archive.org/web/20240918185159/https://www.clubhdtv.com/spectrum-internet-services.html |date=2024-09-18 }}</ref> The word ''spectrum'' was first used by scientists studying [[optics]]. They used the word to describe the [[rainbow]] of colors in visible light when separated using a [[Prism (optics)|prism]]. The spectrum seen when light passes through a prism is an example of the [[dispersion]] of light. The material from which the prism is made has a different [[refractive index]] ''n'' than air. U