2.20 Calculate the wavelength of an electron moving with a velocity of 2.05 × 107 m s–1.


According to de Broglie’s equation,
λ = hmv
Where, λ = wavelength of moving
particle m = mass of particle v =
velocity of particle h = Planck’s constant
Substituting the values in the expression of λ:
λ = 6.626 x 10-34 Js9.10939 x 10-31 kg2.05 x 107 m/s
λ = 3.548 x 10-11 m
Hence, the wavelength of the electron moving with a velocity of 2.05 × 107 m/s is 3.548 × 10-11 m.