**Problem:**

What is the wavelength of an electron moving at 5.31 x 10

^{6}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 10

^{6}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 10

^{6}m/sec is 1.37 x 10

^{-10}m or 1.37 Å.