Mass of the electron = 9.1 x 10 ^ -28g = 9.1 x 10 ^ -31kg Velocity of the electron = 1.7 x 10 ^ 4 We have Planck Constant h = 6.626 x 10 ^ -34 Wavelength of the electron w = h/mv w = 6.626 x 10 ^ -34 / ((9.1 x 10 ^ -31)(1.7 x 10 ^ 4)) = 6.626 x 10 ^ -34 / 15.47 x 10 ^ -27 = 0.428312 x 10 ^ -7 = 4.28 x 10 ^ -8 m