BRAINCAKELine Spectra
When the light from a hot, low-pressure gas (for example in a discharge tube) is passed through a diffraction grating or a prism, it does not produce a continuous spectrum. Instead, a series of separate bright lines of particular colours is seen on a dark background. This is a line emission spectrum.
Each line is produced by electrons de-exciting between two particular energy levels. Because the energy levels are discrete, only certain photon energies, and so certain wavelengths, can be emitted:
λ = hc / (E1 − E2)
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Key terms in this lesson
- energy level
- One of the discrete, fixed values of energy that an electron in an atom can have.
More in Quantum Physics
- DeBroglie Wavelength
- Electron Microscopes
- Electron Energy Levels
- Excitation and De-excitation
- Exam Question 1
- Exam Question 2
- Exam Question 3
- Exam Question 4
All 21 lessons in Quantum Physics · All Edexcel AS-level Physics topics