ABSORPTION SPECTRA Meaning and
Definition
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Absorption spectra refer to the pattern of absorption of electromagnetic radiation by a substance across different wavelengths or frequencies. It is a characteristic feature of a material that helps identify its composition and physical properties.
When electromagnetic radiation, such as light, passes through a sample material, certain wavelengths are absorbed while others are transmitted or scattered. The absorption spectrum is obtained by measuring the intensity of the transmitted or scattered radiation as a function of wavelength. This spectrum typically consists of a series of peaks and valleys, with each peak corresponding to the absorption of radiation at a specific wavelength.
The absorption spectrum of a substance is determined by the arrangement and energy levels of its atoms, molecules, or subatomic particles. Each substance has a unique set of energy levels, and thus its absorption spectrum serves as a signature that can be used to identify the substance. Moreover, the absorption spectrum can provide information about the chemical bonds, electronic structure, and physical properties of the material, such as its color or optical density.
Absorption spectra find applications in various fields, including chemistry, physics, and astronomy. In chemistry, they are used to analyze the composition of unknown substances or verify the purity of samples. In physics, absorption spectra help understand energy transitions in atomic and molecular systems. In astronomy, absorption spectra of stars and galaxies enable scientists to determine their composition and study their chemical evolution.
Etymology of ABSORPTION SPECTRA
The word "absorption" can be traced back to the Latin word "absorbere", which means "to swallow up" or "to take in". "Spectra", on the other hand, is the plural of the Latin word "spectrum", which means "appearance" or "image". In the context of light, spectrum refers to a range of colors produced when white light is dispersed, such as through a prism. Hence, the term "absorption spectra" is derived from the combination of "absorption" and "spectra", which refers to the range of colors or wavelengths that are selectively absorbed by a substance.
