Beer’s lawA law stating that the concentration of an analyte is directly proportional to the amount of light absorbed, or inversely proportional to the logarithm of the transmitted light.
A = abc = log(100/%T) 2 - log %T
A = absorbance
a = absorptivity
b = light path of the solution in cm
c = concentration of the substance of interest
%T = per cent transmittance—the ratio of transmitted light to incident light