What is the principle of absorbance in UV-Vis spectroscopy?

The principle of absorbance in UV-Vis spectroscopy is fundamentally based on the relationship between light absorption, concentration, and path length, which is described by Beer-Lambert Law. According to this law, the absorbance (A) of a substance is directly proportional to its concentration (c) and the path length (l) that the light travels through the sample. This means that as the concentration of the absorbing species increases or as the path length of the light increases, more light is absorbed, leading to higher absorbance values.

This relationship allows chemists to quantify the concentration of a substance in a solution by measuring how much light is absorbed at specific wavelengths. The linearity of this relationship across certain concentration ranges makes UV-Vis spectroscopy a powerful analytical tool in various fields, such as environmental analysis, quality control in manufacturing, and biochemical assays.

In contrast, other options do not accurately reflect the core principle of absorbance in the context of UV-Vis spectroscopy. For example, the intensity of light emitted pertains more to fluorescence or luminescence, light absorption being related to temperature involves complex interactions not solely governed by absorbance, and light scattering typically indicates particle size and shape rather than direct concentration measurement. Thus, the focus on the proportionality