School of Physics Lecture Demonstration Manual

Of-7 Absorption Lines of Sodium

Published: Wednesday 15 March 2006 - Updated: Monday 28 March 2011


To demonstrate that sodium vapour absorbs wavelengths equal to its emission spectra.



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Absorption Lines of Sodium


Sodium Absorption Lines


A white light source from a slide projector is directed onto a high quality diffraction grating located on the prism table of the student spectrometer. A continuous spectrum is displayed on the monitor. A bunsen burner located directly in front of the entrance slit of the spectrometer heats a wire grid that has been coated with table salt. The distinct dark absorption lines of sodium appear in the yellow region of the visible spectrum.

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Electrical safety 

Fire/Burn safety 

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