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Hydrogen spectrum
Intermediate
Lyman, Balmer and Paschen series.
1/λ = R(1/n₁²−1/n₂²)Photons emitted when electrons fall: 1/λ = R(1/n_f² − 1/n_i²). Series: Lyman (to n = 1, UV), Balmer (n = 2, visible), Paschen (n = 3, IR).
Balmer Hα (3→2): 656 nm red.
Each series ends at a series limit.
In more detail
The hydrogen spectrum consists of discrete lines grouped into series, such as the Lyman, Balmer and Paschen series. Each line corresponds to a transition between two energy levels.
Real-world uses
- Astronomers identify hydrogen in stars from its spectral lines.
- The Balmer lines are visible and used in teaching spectroscopy.
- Astronomers identify hydrogen in distant galaxies by its Balmer lines, which are visible series of spectral lines.
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Frequently asked questions
What is the Balmer series?
Transitions that end at n equal to two, producing visible lines.
Why are the lines discrete?
Because electrons can only occupy specific energy levels.
What is the difference between the Lyman and Balmer series?
Lyman lines end in the ground state and are ultraviolet, while Balmer lines end in the second level and include visible red light.
Related topics in Atomic & Nuclear Physics
Bohr's postulates · Radius of Bohr orbit · Energy of hydrogen levels · Rydberg constant · Absorption and emission spectra · Ionisation energy