English: An overview of electromagnetic radiationabsorption. This example discusses the general principle using visible light as specific example. A white beam source -- emitting light of multiple wavelengths -- is focused on a sample (the complementary color pairs are indicated by the yellow dotted lines). Upon striking the sample, photons that match the energy gap of the molecules present (green light in this example) is absorbed in order to excite the molecule. Other photons transmits unaffected and, if the radiation is in the visible region (400-700nm), the transmitted light appears as its complementary color. By comparing the attenuation of the transmitted light with the incident, an absorption spectra can be obtained.
{{Information |Description={{en|1='''An overview of [http://en-two.iwiki.icu/wiki/electromagnetic_radiation electromagnetic radiation] [http://en-two.iwiki.icu/wiki/absorption_spectroscopy absorption]'''. This example discusses the general principle usin