Difference Between Emission And Absorption Spectra

Difference Between Emission And Absorption Spectra: In spectroscopy, two types of spectra are used emission spectra and absorption spectra. The study of the interaction between matter and electromagnetic radiation is known as spectroscopy. The electromagnetic radiation spectrum produced when an electron changes from a high energy state to a lower energy state is known as the emission spectrum of a chemical element or chemical compound.

Spectra of both sorts offer information about the energy levels of molecules as well as atoms. When electrons absorb energy from their ground state to reach higher energy states, they emit light at frequencies with dark bands. The emission spectra of each element are distinct. Atoms absorb energy to create this kind of spectrum. They differ, however, in terms of how they are created and the information they give.

In this article, you will read about the difference between emission and absorption spectra, along with their definition, and the spectra of hydrogen atoms.

What is Emission Spectra?

The electromagnetic radiation spectrum produced when an electron changes from a high energy state to a lower energy state is known as the emission spectrum of a chemical element or chemical compound. The energy difference between the two states is equal to the photon energy of the emitted photon. Each atom contains a large number of potential electron transitions, and each transition has a distinct energy difference. An emission spectrum is made up of a variety of transitions that result in various radiated wavelengths. The emission spectra of each element are distinct. Therefore, components in matter with an unknown composition can be identified via spectroscopy. Similar to this, the chemical examination of substances can make use of the emission spectra of molecules. 

What is Absorption Spectra?

When electrons absorb energy from their ground state to reach higher energy states, they emit light at frequencies with dark bands. Atoms absorb energy to create this kind of spectrum. Let’s examine the formation of absorption spectra. A pattern of dark lines is produced when light from any source is transmitted through the solution or vapor. The spectroscope is utilized to investigate this pattern. Various radiation is absorbed by chemicals and elements when it passes through them, depending on the chemical or element in question. In the emission spectrum, colorful lines can be seen exactly where the dark line pattern appears. The resulting spectrum is referred to as the absorption spectrum.

In Emission Spectra electromagnetic radiation spectrum is emitted when an atom or molecule changes from a high-energy state to a lower-energy state. It is useful in determining the makeup of a particular substance. In Absorption Spectra electrons absorb energy from their ground state to reach higher energy states, they emit light at frequencies with dark bands. It can be used to determine an object’s capacity to hold heat and the degree to which it is absorbed.

What is the difference between Emission and Absorption Spectra?

Emission and absorption spectra are distinct in how they reveal the interaction of matter with light. An absorption spectrum illustrates the wavelengths of light that a substance absorbs when it transitions from a lower energy state to a higher one, displaying dark lines or bands at those absorbed wavelengths. Conversely, an emission spectrum displays the specific wavelengths of light that a substance emits as it returns from a higher energy state to a lower one, generating bright lines or bands at those emitted wavelengths. In essence, absorption spectra depict what light a substance absorbs, while emission spectra reveal what light it releases, providing valuable information for various fields, including chemistry and astrophysics.

Tabular Difference Between Emission and Absorption Spectra

The Below Table provides the tabular difference between emission and absorption spectra:

Emission Spectra	Absorption Spectra
The electromagnetic radiation spectrum that is emitted when an atom or molecule changes from a high-energy state to a lower-energy state is known as the emission spectrum of a chemical element or chemical compound.	When electrons absorb energy from their ground state to reach higher energy states, they emit light at frequencies with dark bands. This kind of spectrum results from atoms absorbing energy.
Consist of spectral color lines	Consist of spectral black lines or spaces
It is useful in determining the makeup of a particular substance.	It can be used to determine an object’s capacity to hold heat and the degree to which it is absorbed
Produced when atoms release energy	Produced when atoms absorb energy

Emission and Absorption spectra of Hydrogen Atom

Emission Spectrum of Hydrogen

• When an electron in a hydrogen atom transitions from a higher energy level to a lower one, it releases energy in the form of light. The emitted light corresponds to specific wavelengths or colors.
• The hydrogen emission spectrum consists of a series of distinct and sharp lines in the visible and ultraviolet regions. These lines are called the Balmer series, and each line represents a particular electronic transition.

Absorption Spectrum of Hydrogen

• An absorption spectrum is created when a hydrogen atom absorbs light and undergoes electronic transitions from lower to higher energy levels. In this process, specific wavelengths of light are absorbed by the atom.
• The absorption spectrum of hydrogen, when examined against a continuous light source, shows dark lines or gaps at precisely the same wavelengths as the lines in the emission spectrum.

Conclusion – Emission vs Absorption Spectra

The information contained in emission and absorption spectra is useful for determining the energy levels of atoms and molecules. Absorption spectra are created when something absorbs electromagnetic energy and the transmitted light is measured, whereas emission spectra are created when atoms or molecules release light when they transition back to their ground state. 

FAQs on Difference Between Emission And Absorption Spectra

1. What is Emission Spectra?

The electromagnetic radiation spectrum produced when an electron changes from a high energy state to a lower energy state is known as the emission spectrum of a chemical element or chemical compound.

2. What is Absorption Spectra?

Electrons absorb energy from their ground state to reach higher energy states, they emit light at frequencies with dark bands. Atoms absorb energy to create this kind of spectrum.

3. What processes create emission spectra?

When atoms or molecules are stimulated by an external energy source, such heat or electricity, then release light when they return to their ground state, emission spectra are created.

4. What information can absorption spectra provide?

Absorption spectra may be used to determine the chemical makeup of a sample, determine its concentration, and investigate the electronic and molecular structure of molecules.

5. What is emission and absorption spectra of hydrogen atom?

The emission spectrum of a hydrogen atom consists of specific lines in the visible and ultraviolet regions, such as the Balmer series, representing the wavelengths emitted when electrons transition from higher to lower energy levels. Conversely, the absorption spectrum of hydrogen displays dark lines at the same wavelengths as the emission lines, indicating the energies required to move electrons from lower to higher energy levels.