Which of the following is a correct statement of the Beer-Lambert law ?

Q. Which of the following is a correct statement of the Beer-Lembert law ?

A) The absorbance of a compound in solution is directly proportional to its concentration and inversely proportional to the path length of the cuvette.
B) The absorbance of a compound in solution is directly proportional to both, its concentration and the path length of the cuvette.
C) The absorbance of a compound in solution is inversely proportional to both, its concentration and the path length of the cuvette.
D) The absorbance of a compound in solution is inversely proportional to its concentration and directly proportional to the path length of the cuvette.

... Answer is B)
The absorbance of a compound in solution is directly proportional to both, its concentration and the path length of the cuvette.

The absorbance of a sample is directly proportional to the path length (d), i.e., the thickness of the cuvette in cm, and the concentration (c) of the absorbing species. The relation is expressed by the Beer-Lambert law: A = α cd

The proportionality constant a is specific to a molecular species at a given wavelength and is called the extinction coefficient and has the unit Lg-1 cm-1. It can be calculated from Eq.( i ), if the concentration c is given in gL-1. In analytical chemistry, we often refer to the molar extinction coefficient (ε) (also referred to as the molar absorptivity), given in L mol-1 cm-1. The Beer-Lembert law can be re-written with c in mole L-1. A = ε cd