All integral laws of spectral lines and of atomic theory spring originally from the quantum theory. It is the mysterious organ on which Nature plays her music of the spectra, and the rhythm to which she regulates the structure of the atoms and nuclei.
Spectroscopy is the study of the interaction of electromagnetic radiation in all its forms with matter. Electromagnetic spectrum is the range of all types of electromagnetic radiation. The interaction might give rise to electronic excitations (UV), molecular vibrations (IR) and nuclear spin orientation (NMR).
Electromagnetic energy is used while listening to the radio, watching television, sending a message or popping popcorn in a microwave oven.
Examples: Radio ...