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De Broglie Wavelength Calculator

The De Broglie Wavelength Calculator determines the quantum matter wavelength of moving electrons, protons, neutrons, or custom particles using the fundamental de Broglie relationship λ = h / p.

Select a standard particle or enter custom mass.

Rest mass of particle in kilograms (used if Custom Mass selected).

Velocity of the particle in meters per second.

Calculated Result
7.2739e-1 nmnm

De Broglie Wavelength

Wavelength (Meters)

7.2739e-10 m

Particle Momentum

9.1094e-25 kg·m/s

Kinetic Energy (eV)

2.84 eV

Kinetic Energy (Joules)

4.5547e-19 J

Calculation Breakdown

  1. Momentum Calculation (p = m × v)9.1094e-31 kg × 1.0000e+6 m/s = 9.1094e-25 kg·m/s
  2. De Broglie Relation (λ = h / p)6.6261e-34 J·s / 9.1094e-25 kg·m/s = 7.2739e-10 m (7.2739e-1 nm)
  3. Classical Kinetic Energy (E = ½mv²)0.5 × 9.1094e-31 kg × (1.0000e+6 m/s)² = 4.5547e-19 J (2.84 eV)

Wavelength by Velocity (nm)

Interactive visualization based on your current inputs

Calculated Value
0.01.83.65.57.3100 km/s500 km/s1,000 km/s5,000 km/s

What Is the De Broglie Wavelength Calculator?

The de Broglie wavelength is the wavelength associated with any moving material particle, as proposed by Louis de Broglie in 1924.

This quantum mechanical wave-particle duality explains why electrons exhibit interference patterns and underpins transmission electron microscopy.

How Does the De Broglie Wavelength Calculator Work?

The calculator computes particle momentum p from rest mass m and velocity v.

Wavelength λ is derived by dividing Planck constant h by momentum.

Classical kinetic energy in both Joules and electron-volts (eV) is evaluated alongside wave parameters.

De Broglie Wavelength Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

λ = h / p = h / (m · v)

Matter wavelength λ equals Planck constant h (6.626 × 10⁻³⁴ J·s) divided by momentum p = m · v.

How to Use the De Broglie Wavelength Calculator

  1. Select a preset particle (electron, proton, neutron) or choose Custom Mass.
  2. Specify velocity in meters per second.
  3. Review matter wavelength, momentum, and kinetic energy in the results breakdown.

Step-by-Step Example Calculation

Electron at 1,000,000 m/s

Input Values:

particlePreset:electron
massKg:9.1093837e-31
velocityMS:1000000
Worked Steps: An electron traveling at 1,000,000 m/s has a de Broglie wavelength of approximately 0.727 nm.

Understanding Your Result

Matter wavelengths around 0.1 nm are comparable to atomic lattice spacings in crystal diffraction.

Sub-picometer wavelengths require relativistic corrections at extreme beam voltages.

Factors That Affect the Result

  • Particle Mass: Heavier particles produce vastly smaller de Broglie wavelengths at equivalent velocity.
  • Beam Voltage / Velocity: Higher acceleration speed compresses wavelength proportionally.

When Should You Use This Calculator?

  • Transmission and scanning electron microscopy (TEM / SEM) beam calibration.
  • Quantum mechanics coursework and particle beam accelerator problem sets.

Assumptions & Limitations

  • Non-relativistic approximation valid for particle velocities significantly below the speed of light.

Frequently Asked Questions

Calculation Accuracy & Reference Note

Calculations use the CODATA 2018 exact Planck constant (6.62607015 × 10⁻³⁴ J·s).

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