What does Beer's Law explain?

Beer's Law, also known as Beer-Lambert Law, describes how the absorbance of light is related to the properties of the material through which the light is traveling. Specifically, it establishes a direct relationship between the absorbance of a solution, the concentration of the absorbing species in that solution, and the path length of the light passing through the solution. The law states that absorbance (A) is proportional to the concentration (c) and the path length (l), expressed mathematically as A = εlc, where ε is the molar absorptivity or extinction coefficient. This relationship helps in understanding how varying concentrations of a solution will affect the amount of light absorbed, which is fundamental in analytical chemistry and various applications such as determining concentrations of solutes in solutions using spectrophotometry.