Calculate the wavelength of an electron for a certain energy

[mitochondriaro]

Got a hmwk question here that asks to calculate λ of an electron with a certain amount of energy, and sadly couldn't figure it out. My solns manual does a fantastic job of regurgitating the formula:

E = P² / 2m₀​

to be used to get the numerical soln which is technically all I need but I'm an overachieving nerd and I have no idea how they derived this; I tried messing around with the energy-momentum formula but I still can't see it any ideas?

Thanks a lot!

 

[NascentOxygen]

mitochondria[/URL]ro, post: 4365896"]Got a hmwk question here that asks to calculate λ of an electron with a certain amount of energy, and sadly couldn't figure it out.

Hi mitochondriaro.

Sounds like you'd be looking for its De Broglie wavelength.