Given that,
Mass of electron = 9.11 x 10-31 kg
Velocity of electron v = 5.31 x 106 m/s
Planck's constant h = 6.626 x 10-34 Js
de Broglie equation is ╬╗ = h/mv
╬╗ = 6.626 x 10-34/(9.11 x 10-31 x 5.31 x 106)
= 6.626 x 10-34/4.84 x 10-24
= 1.37 x 10-10 m
= 1.37 ├à
Therefore, the wavelength of the moving electron is 1.37 ├à.