Intensity and Absorbance
A = Absorbance ; Io = Intensity of the incident radiation ; I = Intensity of the transmitted radiation
If a beam of monochromatic light is passed through a solution then the absorbance (formerly known as optical density) can be measured by the experimental values of the original intensity of the beam of light and the intensity of the beam light after passing through the solution. Thus any of this three properties can be readily calculated using this calculator. This is known as the Beer - Lambert Law.