Practice question

Beer-Lambert law exhibits additivity principle for mixtures containing non-interacting absorbing species, each obeying linearity. Total absorbance at given wavelength equals sum of contributions from each chromophore: Ai equals εi times Ci times l. For two absorbers coexisting, total A equals ε1 C1 l plus ε2 C2 l, and when path length constant often simplified as A equals ε1C1 plus ε2C2 per unit length. This additivity underpins dual-wavelength analysis resolving mixtures such as oxy-deoxyhemoglobin, NADH-NAD+, protein-nucleic acid blends by measuring absorbance at two λmax and solving simultaneous linear equations for concentrations.