De Broglie Wavelength Example Problem

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:

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.