wavelengths, the radiations having wavelength shorter than 200 nm are also absorbed by atmospheric gases. Therefore, in order to study the transitions brought about by these radiations in a molecule, the study should be conducted in vacuum.
The light source is usually a hydrogen lamp, and the optical and cells are made up of quartz because most other clear material absorb UV radiation.
Two empirical law has been formulated about absorption intensity.
2) Beer’s law: Beer’s law states that the absorption of a monochromatic radiation by a homogeneous medium is proportional to the number of absorbing molecules.
A ∝ C
|Fig.1 .2 Typical UV spectrum|