Problem relating to the Heisenberg's Principle

[uzair_ha91]

Homework Statement

An electron is placed in a box about the size of an atom that is about 1*10^-10m. What is the velocity of the electron?

Homework Equations

Heisenberg's equation
xp=h/2pi
xmv=h/2pi
v=h/2pi*x*m
where x=1*10^-10m
m=9.1*10^-31kg
h=planck's cosntant

The Attempt at a Solution

Answer is 7.29*10^6

 

[willem2]

Was this REALLY the question? The uncertainty principle states that:

$$\Delta x \Delta p \geq \frac {h} { 4 \pi}$$

NOT

$$x p = \frac {h} { 4 \pi}$$


(I don't know how to do the reduced Planck's constant in Latex)

 

[uzair_ha91]

So it's 4pi not 2pi? Actually the answer I'm getting is different from that which is given at the end of my physics book.
And while solving the problem, doesn't it become $$\Delta$$x$$\Delta$$p=h/4pi?