A moving particle of mass m has a de Broglie wave length λ. Then energy of the particle is
h2/4mλ2
2h2mλ2
mλ22p2
h2/2mλ2
de Broglie wavelength λ=hp⇒p=hλ
∴ kinetic energy=p22m=h/λ22m=h22mλ2