# Beer Lambert Law

The Beer Lambert Law is also known as Beer’s law, Beer-Lambert-Bouguer law or Lambert-Beer law. This law was discovered by Pierre Bouguer before 1729. It is the linear relationship between absorbance and concentration of an absorbing species. While working in concentration units of molarity, the Beer’s law is written as a=e*c*l. Where a is the Absorbance, e is the Molar absorption coefficient, l is the Path Length and c is the Concentration.

### Calculate Absorbance using Beer’s Law

Molar Absorption Coefficient

Concentration

Path Length

length

Absorbance

### Formula Absorbance using Beer’s Law

Absorbance = Molar Absorption Coefficient x Path Length x Concentration

### Example Absorbance using Beer’s Law

For a substance with molar absorption coefficient 50 m^{2}/mol, concentration 10 mol/L and path length 5 m, the absorbance using beer’s lambert law can be calculated as

= 50 x 5 x 10

=2500