Given the relationships: \lambda = \frac{h}{p} = \frac{h}{mv} and E = hf for wavelike non-relativistic matter, and v = \lambda f for a general wave, one can obtain the result:
E = \frac{h^2}{m \lambda^2}.
Whilst for particulate matter, we have E = \frac{1}{2}mv^2, which when combined with the...