1. Feb 7, 2005

LakeMountD

The deBroglie wavelength of an electron which moves with a speed of .0320 c is
7.18x10^-12

What is the fundamental minimum uncertainty in a measurement of the position of the elctron in the previous prolem if its momentum is simultaneouslymeasured to a precisioin of plus or minus one percent (two percent total)?

2. Feb 7, 2005

dextercioby

1.Compute "p_{x}".
2.Compute \Delta p_{x}.
3.Compute \Delta x from the HUP.

Daniel.

3. Feb 7, 2005

Justin Lazear

$$\Delta p \Delta x \geq \frac{\hbar}{2}$$

The problem states that the electron is moving .320 times the speed of light. The mass of the electron is known. The uncertainty in the momentum is .02p ($\Delta p = .02 p = .02mv$).

The only value in the above inequality you don't know is the uncertainty in position.

--J

Last edited: Feb 7, 2005
4. Feb 7, 2005

dextercioby

1.Justin,the sign in the HUP is inverse than the one u posted... :tongue2:
2.And it should be
$$\Delta p_{x} \Delta x \geq \frac{\hbar}{2}$$

There's a huge difference between your (initial,in the case u edit it) formula and the one i've written.Can u see why...?

Daniel.

Last edited: Feb 7, 2005
5. Feb 7, 2005

Justin Lazear

Those darned TeX letters confuzzled me! leq, geq, bah!

--J