where, λ is wavelength h is Planck's constant (6.626×10−34‌Js) m is mass of electron (given 9.0×10−31‌kg ) v is velocity of electron (given 2.2×106m∕s ) ‌begin‌aligned∴‌‌λ‌=‌
6.626×10−34
9.0×10−31×2.2×106
‌=0.33×10−9m‌end‌aligned ‌‌ i.e. ‌0.33‌nm‌ (as ‌1‌nm=10−9m‌ ) ‌