Spectrophotometry is one of the most important practices carried out in physics laboratories. Spectrophotometry is the study of the reflection or transmission properties of a substance as a function of wavelength. It is the quantitative study of electromagnetic spectra of a material. During the process, the transmittance or reflectance of the substance is measured through the careful geometrical and spectral consideration.
To carry out spectrophotometry, a spectrophotometer is required. A spectrophotometer is a device or more specifically a photometer that is used to measure intensity of light as a function of the wavelength of light. Different types of spectrophotometers are found in the market. They are classified on various basis. The most important distinctions used to classify them are:
Principle of Spectrophotometry
A spectrophotometer, one of the most useful physics lab equipments is the combination of two devices, a spectrometer and a photometer. Spectrometer is used for producing light of any selected wavelength or color while a photometer is used for measuring the intensity of light. The two devices are placed at either side of a cuvette filled with a liquid. Spectrometer produces the light of desired wavelength and it passes through the tube and reaches photometer that measures its intensity. Then the photometer produces a voltage signal to a display device, usually a galvanometer. As the amount of light absorbed by the liquid changes the signal also changes. The concentration of a substance in solution can be measured by calculating the amount of absorption of light at the appropriate wavelength or a particular color.