Biology 2290F/G Study Guide - Final Guide: Diffraction Grating, Phototube, Radiant Energy

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Numbering refers to the general course objective numbering on review sheet. Radiant energy of wavelengths 340nm 900nm is supplied by a tungsten lamp. The light is focused on a diffraction grating which splits the light into its component wavelengths (like prism) Wavelengths are selected by changing the position if the diffraction grating. This way light of narrow range wavelength passes through the slit before the sample. Any light not absorbed by the sample goes to a phototube. It instead measures the amount of light transmitted by a sample. This transmittance is then compared to the reference blank (see #4) to determine how much light has been absorbed by the sample: describe transmittance and absorbance. Transmittance is the fraction of incident light that passes through the sample. Absorbance is the amount of light absorbed by the sample. A = 1. 59 x 10-1: state lambert"s law and beer"s law in words.