De Broglie Wavelength Calculator
Matter-wave wavelength λ = h/p. Enter mass and velocity, or momentum directly.
Formulas
p = m · v
λ = h / p with h = 6.626×10⁻³⁴ J·s
λ = h / p with h = 6.626×10⁻³⁴ J·s
Physics behind the de Broglie wavelength
In 1924, Louis de Broglie proposed that every particle behaves, in some sense, like a wave. The wavelength λ is inversely proportional to momentum p, meaning fast or heavy particles have very short wavelengths. Electrons in an atom have λ comparable to atomic sizes, which is why they form standing-wave orbitals. Experimentally, the Davisson–Germer experiment in 1927 demonstrated electron diffraction — a direct confirmation of de Broglie's hypothesis.
Worked example
Electron at v = 10⁶ m/s
p = 9.109×10⁻³¹ · 10⁶ = 9.109×10⁻²⁵ kg·m/s λ = 6.626×10⁻³⁴ / 9.109×10⁻²⁵ ≈ 7.27×10⁻¹⁰ m (0.727 nm)
Related tools
FAQs
What is the de Broglie hypothesis?
Every moving particle has an associated wave of wavelength h/p.
Why don't we see the wavelength of a baseball?
It's around 10⁻³⁴ m — far below any measurement.