Uncertainty Principle, Energy and Position

[MrJohnnyPrice]

Homework Statement

Electrons in atoms are known to have energies in the range of a few eV. Show that the uncertainty principle allows electrons of this energy to be confined in a region the size of an atom (0.1 nm)

Homework Equations

$$\Delta$$x$$\Delta$$p $$\geq$$ h bar / 2

$$\Delta$$E$$\Delta$$t $$\geq$$ h bar / 2

The Attempt at a Solution

h bar = 6.58 x 10^-16 eV * s
$$\Delta$$x = .1 nm

I know that if there was an uncertainty relationship between Energy and displacement I could set h bar and $$\Delta$$x to the values given and show that this is possible, but I can't figure out how to find an energy position uncertainty relation.

 

[Feldoh]

1/2mv^2 and mv look an awful lot a like...