In the context of spectrometry, what does transmittance measure?

Transmittance is a key concept in spectrometry that refers to the measurement of the amount of light that passes through a solution. This measurement is critical because it helps determine how much light is absorbed by the solution, which can be related to the concentration of the solute based on Beer-Lambert law.

In spectrometric analysis, different substances absorb varying wavelengths of light to different extents. By measuring how much light transmits through the sample compared to the initial intensity of light, one can infer information about the concentration of the absorbing species in the solution. Transmittance can be expressed as a percentage, indicating how much of the light has successfully passed through the sample.

This focus on the passage of light is central to understanding the interaction between light and matter in a spectroscopic context, distinguishing transmittance from other measurements like concentration, temperature, or sound wave absorption, which do not relate directly to light transmission through a medium.