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CHEM 403 - Seminar: Spectra

What is a Spectrum?

According to the Oxford English Dictionary:  

a. The coloured band into which a beam of light is decomposed by means of a prism or diffraction grating. Also, a dark band containing bright lines produced similarly; such a (coloured or dark) band, or the pattern of lines in it, as characteristic of the light source; hence, the pattern of absorption or emission of light or other electromagnetic radiation over any range of wavelengths exhibited by a body or substance.

The first known use of the word "spectrum" was:  
1672    I. Newton in  Philos. Trans. 1671 (Royal Soc.) 6 3076   Comparing the length of this coloured Spectrum with its breadth, I found it about five times greater.

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