λ de Broglie

λ = h/p.
Created by
Renato Passos, Eng. de Software
Reviewed by
Renato Passos, Eng. de Software

Last updated: Apr 18, 2026

λ (m)
0,00000000066261 m

About this calculator

The de Broglie wavelength calculator determines the wavelength associated with moving particles based on quantum theory. Louis de Broglie's hypothesis states that all matter exhibits wave-like properties, with wavelength λ = h/p, where h is Planck's constant and p is momentum. This principle is foundational in quantum mechanics and wave-particle duality studies.

The tool calculates λ by either directly using momentum (p = mass × velocity) or by applying the formula λ = h/(m·v). Input units must be consistent: mass in kg, velocity in m/s, and Planck's constant as 6.626×10⁻³⁴ J·s. Results are typically on the order of picometers or smaller, highlighting the quantum scale of this phenomenon.

This calculator is commonly used in electron diffraction experiments, particle physics, and nanoscale material studies. In macroscopic objects, the de Broglie wavelength is negligible due to large masses, but it becomes significant for subatomic particles like electrons in electron microscopes or accelerators.

Key considerations: Ensure momentum is calculated correctly (mass×velocity), and remember that relativistic effects become relevant at velocities near the speed of light. For educational purposes or low-speed applications, the classical formula suffices.

Frequently asked questions

What are the correct units for inputting values?

Mass in kg, velocity in m/s, and results will be in meters. Planck's constant (h) is internally set to 6.626×10⁻³⁴ J·s.

What if the momentum is zero?

If momentum is zero (stationary particle), the wavelength theoretically approaches infinity, which is not physically meaningful in practice.

Does this calculator work for macroscopic objects?

No, the effect is negligible for large objects due to extremely small wavelengths, but critical for subatomic particles like electrons.

Why is λ = h/p only valid for massive particles?

Massless particles like photons require different formulas involving energy and relativistic momentum calculations.

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