Science / Chemistry / Transmittance: The transmittance is the fraction of radiant intensity transmitted by a sample, T = I/I0 where T is the transmittance and I, I0 are the radiant intensity of the radiation after and before passing through the sample. The percent transmittance is the transmittance times 100%.


Science / Chemistry / Absorbance: (A, D, E) optical density; extinction; decadic absorbance. A measure of the amount of light absorbed by a sample. The absorbance (A) equals minus the base-10 log of the transmittance. MORE

Absorption Spectrum

Science / Chemistry / Absorption Spectrum: A plot that shows how much radiation a substance absorbs at different wavelengths. Absorption spectra are unique for each element and compound and they are often used as chemical 'fingerprints' in ana MORE