Spectrophotometry is a method used in chemistry to measure the amount of light that a chemical substance absorbs by determining the intensity of light as a beam of light passes through sample solution.
This refers to the capacity of a substance to absorb radiation, measured by the degree to which it impedes the transmission of light.
Transmittance: This is the fraction of incident light at a specified wavelength that passes through a sample.
It's the distance between successive crests or troughs in waves, such as those in sound or electromagnetic radiation.