What is the Difference Between Emission and Absorption Spectra?

The main difference between emission and absorption spectra lies in the processes that produce them and the information they provide about the substance being observed. Here are the key differences:

• Emission Spectrum: An emission spectrum is formed when energy is absorbed by electrons of an atom, causing them to move from lower energy levels to higher energy levels. The excited electrons then radiate energy to return to their ground states, and the emission spectrum is formed by the frequencies of this emitted light. Emission spectra have different colored lines in the spectrum, representing the specific wavelengths at which the substance emits light.
• Absorption Spectrum: An absorption spectrum is constituted by the frequencies of light transmitted with dark bands when an atom or molecule absorbs photons with energies equal to the difference between two energy levels. In an absorption spectrum, there are dips or dark lines in the spectrum, indicating the wavelengths at which light has been absorbed by the substance.

In summary:

• Emission spectra have colored lines, indicating the wavelengths at which the substance emits light.
• Absorption spectra have dark lines, indicating the wavelengths at which the substance absorbs light.

These spectra can be used to identify the elements present in a substance, as each element has its unique set of energy levels and corresponding wavelengths of emitted or absorbed light.

Comparative Table: Emission vs Absorption Spectra

The main difference between emission and absorption spectra lies in the way they are formed and the information they provide. Here is a comparison table highlighting the key differences between the two:

In summary, emission spectra are formed when electrons release energy as they fall to lower energy states, while absorption spectra are formed when electrons absorb energy and move to higher energy states. The resulting spectra appear as brightly colored lines (emission) or dark-colored lines (absorption) superimposed on a continuous spectrum. These spectra provide valuable information for various fields, such as chemistry, astrophysics, and molecular biology.