Spectrum Analysis is the study of electromagnetic interactions of matter in order to determine its chemical and physical properties. The analysis of spectra originated through the study of visible light which was dispersed using a prism. Nowadays, the concept has expanded to include any type of interaction regarding electromagnetic energy.
The actual spectrum for analysis is usually presented as a variable of interest as a function of either wavelength or frequency. However, spectroscopic studies can deviate from this norm, such as in mass spectrometry, where relative abundance is compared to mass-to-charge ratio to determine the elemental composition and the chemical structures of molecules.
Although Spectrum Analysis may seem very broad, it actually can be classified based on the nature of the interaction. These interactions include: absorption, emission, elastic scattering and inelastic scattering just to name a few. Thus, understanding spectra and how to read them is a useful tool to understand the electromagnetic interactions, as well as the physical and chemical properties of matter.