Chemistry Notes for B.Sc. and M.Sc.

The Beer-Lambert Law   states that   the absorbance of light by a medium is direct ly proportional to   its concentration   as well as path length (the distance travelled by the light) . The law can be expressed mathematically as: A   = ϵcl   = log( I 0 /I) Where:   A   = A bsorbance (measure of the amount of light absorbed).   ·  I 0 = Intensity of incident Light ·  I = Intensity of transmitted Light ·  ϵ   =   M olar absorptivity   Constant   ·  c =   the concentration of the solute ·  l =   the path length of the sample (the distance light travels through the solution ) Units: ·  A   = unitless ·  ϵ   =   cm 2 /mol ·  c =   mol/L ·  l =  cm M olar absorptivity   Constant ( ϵ )   --- A   constant that indicates how strongly a substance absorbs light at a particular wavelength.   It is characteristic of a substance and is i...