de Broglie wavelength calculator
Every moving particle has a wavelength of h over its momentum. For anything macroscopic it is unimaginably small.
kg
de Broglie wavelength
7.2738951e-10m
- Same wavelength
- 0.727 389 51 nm
- Momentum
- 9.1093837e-25 kg m/s
- Kinetic energy
- 2.842 815 1 eV
Show the working
- Mass = 9.10938e-31
- Velocity = 1 000 000
- Momentum = 9.10938e-31 * 1 000 000 = 9.10938e-25
- de Broglie wavelength = h / 9.10938e-25 = 7.2739e-10
- Same wavelength = 7.2739e-10 * 1e9 = 0.727 39
- Kinetic energy = 9.10938e-31 * 1 000 000^2 / 2 / qe = 2.842 82
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- lambda = h / (m v)
An electron at a million metres per second has a wavelength of 0.73 nm — comparable to atomic spacing, which is why electron diffraction works.
A 70 kg person walking has a wavelength around 10^-36 m, which is why nobody diffracts through doorways.