Beer’s Law

If light is allowed to pass through a colored solution, the solution will absorb some light, while the rest of it will be transmitted. The amount of light absorbed is proportional to the nature, concentration and color of the solution.

Lambert’s Law

The light absorbed by the colored solution is directly proportional to the light path of the color solution (diameter of the cuvette): that is, if the cuvette diameter is doubled, the light absorbed will be doubled.

The following video explains in detail the concepts of Beer Lambert’s law and how the concepts are applied in equipment like the spectrophotometer.