Copyright © University of Cambridge. All rights reserved.

'Light Absorbance' printed from

Show menu


If you can see this message Flash may not be working in your browser
Please see to enable it.

The molar extinction coefficient $\epsilon(\lambda)$ of a chemical measures theintrinsic property of how the chemical absorbs light of wavelength $\lambda$. When such light passes through a homogeneous solution of the chemical, the absorbance $A$ is measured by the Beer-Lambert law $A=\epsilon(\lambda) cL$, where $c$ is the concentration of the chemical and $L$ is the path length of the light passing through the solution. Recall that 1 katal = 1 mole per second.
With thanks to Keith Johnstone for providing the template for this question.