# Uncertainty & Bohr model

1. Oct 22, 2007

### 84527

Why the uncertainly relation ΔxΔp>h forces us to reject the semiclassical Bohr model for the hydrogen atom?

2. Oct 22, 2007

### chaoseverlasting

This is fairly easy to prove, the diameter of the atom is of the order of $$10^{-15}$$. Therefore an electron MUST be present in the volume of the atom. So, the maximum uncertainty that can be allowed is $$10^{-15}m$$. Plug this into the equation and what do you get for the uncertainty in velocity?

HINT: Its greater than the speed of light, and thats just the UNCERTAINTY!

And the equation is $$dx\times dp>=\frac{h}{4\pi}$$.