A matter wave’s de Broglie wavelength is Planck’s constant divided by momentum magnitude.
Difficulty
Intermediate
Read time
5 min
Prerequisites
Basic algebra, consistent units, and the stated model assumptions
Source
OpenStax, College Physics 2e, §29.6 (Paul Peter Urone and Roger Hinrichs)OpenFormulaGraph equation reference; FormuLab adaptation details and license are provided below.
Adapted from OpenFormulaGraph, under CC BY 4.0.
FormuLab adapted wording, notation, applicability conditions and topic placement, and expanded the numerical check into a worked example. The textbook section reference was corrected.
A matter wave’s de Broglie wavelength is Planck’s constant divided by momentum magnitude. At relativistic speeds the momentum must be relativistic, rather than the classical mass-times-speed approximation.
| Symbol | Meaning | Units |
|---|---|---|
| Wavelength | ||
| Planck's Constant | ||
| Momentum |
Estimate wavelength from particle momentum.
Compare quantum wavelengths for different momenta.
Find the de Broglie wavelength for particle momentum magnitude 1.00 × 10⁻²⁴ kg·m/s.
OpenFormulaGraph equation reference; FormuLab adaptation details and license are provided below.
Adapted from OpenFormulaGraph, under CC BY 4.0.
FormuLab adapted wording, notation, applicability conditions and topic placement, and expanded the numerical check into a worked example. The textbook section reference was corrected.
Assumptions
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