What is the difference between spectrophotometry and spectroscopy?

Spectrophotometry 

Spectrophotometry is a technique that is used to measure the amount of light a chemical substance absorbs. It involves passing a light beam through the target chemical substance and measuring the intensity of light absorption. 

Spectrophotometry is based on the principle that all chemical compounds absorb, transmit, or reflect light over a specific wavelength spectrum. A spectrophotometer is used to measure the material’s reflectance or transmission properties as a wavelength function. This technique produces measurable outcomes. 

Spectrophotometry is widely used in physics, biology, chemistry, biochemistry, and clinical studies. 

Spectroscopy 

Spectroscopy is not a technique. It is the study of the interactions between electromagnetic radiation and a particular matter of interest.

It is based on the principle that matter gets excited and produces an interaction when it gets excited. This interaction can be observed easily through visible light produced by electromagnetic waves. 

A spectrometer is used to measure physical variations across a spectrum and gather information based on the amount of visible, ultraviolet or infrared light that is projected by the material. Spectroscopy does not produce measurable outcomes. 

Spectroscopy is widely used in several scientific fields including chemistry, physics, and astronomy.