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 \Deltax\Deltap=h/4pi?