Louis de Broglie proposed in 1924 that matter has wave properties. Electrons in a microscope have wavelengths around 100,000 times shorter than visible light, revealing atoms; a thrown ball’s wavelength is far too small ever to notice.
How to use the De Broglie Wavelength Calculator
- Calculate from
- Particle
- Mass
- Velocity
- Momentum p
Results update as you type, every field has its own unit menu, and everything is calculated in your browser.
How it works
Choose the particle (or a custom mass) and enter its speed, or switch to entering the momentum.
Inputs explained
| Field | What to enter |
|---|---|
| Calculate from | Choose one: Mass and velocity, Momentum |
| Particle | Choose one: Electron, Proton, Neutron, Muon … |
| Mass | Units: kg, g, u (Da) |
| Velocity | Units: m/s, km/s, c, km/h |
| Momentum p | Units: kg·m/s, keV/c, MeV/c |
Example values
How the main result changes when Mass changes and everything else stays at the example values above:
| Mass (kg) | De Broglie wavelength λ (nm) |
|---|---|
| 0.0725 | 0.7274 |
| 0.1087 | 0.7274 |
| 0.145 | 0.7274 |
| 0.1813 | 0.7274 |
| 0.2175 | 0.7274 |
| 0.29 | 0.7274 |
Formula
λ = h/p, p = γ·m·v
Worked example
Inputs — Calculate from: Mass and velocity; Particle: Electron; Velocity: 1,000,000 m/s.
Results — Momentum = 9.1094e-25 kg·m/s; De Broglie wavelength λ = 0.727385 nm.
Key terms
- Matter wave
- Wave associated with a moving particle.
Frequently asked questions
Do everyday objects have a wavelength?
Yes, but it is absurdly small – about 10⁻³⁴ m for a ball.
Why do electron microscopes use electrons?
Their short wavelength resolves much finer detail than light.
Was it confirmed?
Yes – Davisson and Germer saw electron diffraction in 1927.
Why the relativistic correction?
Fast particles' momentum is γmv.