De Broglie Wavelength Example Problem

Finding the Wavelength of a Moving Particle

It's not hard to calculate wavelength if you know how to use the de Broglie equation.
It's not hard to calculate wavelength if you know how to use the de Broglie equation. Justin Lewis, Getty Images
By
Todd Helmenstine
Todd Helmenstine
Todd Helmenstine is a science writer and illustrator who has taught physics and math at the college level. He holds bachelor's degrees in both physics and mathematics.
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Updated on June 05, 2019

This example problem demonstrates how to find the wavelength of a moving electron using de Broglie's equation.​ While an electron has properties of a particle, the de Broglie equation may be used to describe its wave properties.

Problem:

electrons
Read More
de Broglie Equation Definition
By Anne Marie Helmenstine, Ph.D.

What is the wavelength of an electron moving at 5.31 x 106 m/sec?
Given: mass of electron = 9.11 x 10-31 kg
h = 6.626 x 10-34 J·s

Solution:

de Broglie's equation is
λ = h/mv
λ = 6.626 x 10-34 J·s/ 9.11 x 10-31 kg x 5.31 x 106 m/sec
λ = 6.626 x 10-34 J·s/4.84 x 10-24 kg·m/sec
λ = 1.37 x 10-10 m
λ = 1.37 Å

Answer:

The wavelength of an electron moving 5.31 x 106 m/sec is 1.37 x 10-10 m or 1.37 Å.

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Helmenstine, Todd. "De Broglie Wavelength Example Problem." ThoughtCo, Aug. 25, 2020, thoughtco.com/de-broglie-wavelength-example-problem-609472. Helmenstine, Todd. (2020, August 25). De Broglie Wavelength Example Problem. Retrieved from https://www.thoughtco.com/de-broglie-wavelength-example-problem-609472 Helmenstine, Todd. "De Broglie Wavelength Example Problem." ThoughtCo. https://www.thoughtco.com/de-broglie-wavelength-example-problem-609472 (accessed April 19, 2024).