The amount of the light absorbed depends only on the no of molecules of the absorbing substance that can interact with the light. The absorbance is the same if the cuvette has the path length L, but concentration of the solution is doubled. A = ABC (Beer‟s law), C = Path length of the cuvette,
B = Concentration of the absorbing substance, A = Absorbtivity, a factor that depends on the absorbing substance.