The mathematical expression of Lambert-Beer law A=lg( 1/T)=Kbc Lambert law points out that the proportion of light absorbed by transparent media has nothing to do with the intensity of incident light; In the optical path, each layer of medium with the same thickness absorbs the same proportion of light. Beer's law points out that the amount of absorbed light is directly proportional to the number of molecules that produce light absorption in the optical path. Log (Io/I) = ε Cl (1-4), where Io and I are the intensities of incident light and transmitted light respectively after passing through the sample; Log(Io/I) is called AB-sorbence, or optical density. C is the sample concentration; L is the optical path; ε is the proportional coefficient of light absorption. When the concentration adopts molar concentration, ε is the molar absorption coefficient. It is related to the nature of the absorbing substance and the wavelength λ of the incident light. When the substance that produces ultraviolet absorption is unknown, its absorption intensity can be expressed as: (1-5) where c is the number of grams of solute in lOOml solution; B is the optical path in centimeters; A is the ultraviolet absorption produced by the solution; Represents the absorption generated when the optical path and substance concentration of lcm are 1g/ 100ml. The mathematical expression of Lambert-Beer's Law A=lg( 1/T)=Kbc A is absorbance and T is transmittance, that is, the ratio of the intensity of transmitted light to the intensity of incident light C is the concentration of light-absorbing substance B is the thickness of absorption layer. Its physical significance is that when a beam of parallel monochromatic light passes through a uniform non-scattering light-absorbing substance vertically, its absorbance A is directly proportional to the concentration of light-absorbing substance C and the thickness of absorption layer B, as shown in Higher Education Press. 2 1 century textbook series, analytical chemistry, 3rd edition (1), chapter 10, section 2, basic law of light absorption, premise of Lambert-Beer law (1), incident light is parallel monochromatic light, and it is irradiated vertically, and (2) light-absorbing substances are