Spectrophotometer

Is a branch of electromagnetic spectroscopy concerned with the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength Spectrophotometer uses photometers, known as spectrophotometers which can measure the intensity of a light beam at different wavelengths, although spectrophotometer is most commonly applied to ultraviolet, visible, and infrared radiation, modern spectrophotometers can interrogate wide swaths of the electromagnetic spectrum, including x-ray,  ultraviolet, visible, infrared, and/or microwave wavelengths.