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sodper

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**[SOLVED] Help with understanding the uncertainty principle**

I may have posted this in the wrong forum. If so I am sure a moderator could move it to the correct one.

Problem statement:

I have an assignment in which I need to calculate the lowest possible mean of an electron's KE , <KE>, based on the uncertainty of the electron's moment.

Given data:

The radius in which the electron is allowed to move, d=2.81*10^-10

Attempt at solution:

The uncertainty of the electrons position corresponds to d, deltax=d

Using the uncertainty principle I got, deltap = hbar/(2*deltax), where deltap is the lowest possible deviation.

I got deltaKE from, deltaKE = deltap^2/(2m), (m is the electron mass)

A fellow student explained to me that because my problem involves a stationary system (an electron bound to an atom), <KE> should be zero, which gives me:

(deltaKE)^2 = <KE^2> - <KE>^2 => (deltaKE)^2 = <KE^2>

But how do I proceed from here?

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