- #1

Ng Yau Ming

- 8

- 2

- Homework Statement
- The uncertainty in the position of an electron along an x axis is given as 28 pm. What is the least uncertainty in any simultaneous measurement of the momentum component px of this electron?

- Relevant Equations
- (Uncertainty in x)*(Uncertainty in momentum in x) >= hbar/2

hbar=h/(2*pi)

I know Heisenburg's Uncertainty Principle states that there has to be a minimum amount of uncertainty. Where the minimum uncertainty is hbar/2.

My attempt at the solution

Uncertainty in x = 28E-12 m (Turn pm into m)

h=6.63E-34 (constant)

hbar=1.055`19E-34 (constant)

hbar/2 = 5.275986363E-35 (constant)

Since the formula is

(Uncertainty in x)*(Uncertainty in momentum in x) >= hbar/2

and that it is asking for the minimum uncertainty, therefor minimum amount of uncertainty would be when it is hbar/2

(Uncertainty in x)*(Uncertainty in momentum in x) = hbar/2

So to calculate uncertainty in momentum

(Uncertainty in momentum in x)= (hbar/2)/(Uncertainty in x)

The answer I got is 1.884280844E-24

However this is wrong.

The only thing I can think of is that I got my magnitudes wrong? 28 pm should be 28E-12 m correct?

Im terribly sorry. I know this should be a simple question but I cannot figure out what is wrong with my calculations.

Assistance would be much appreciated.

Thank you.

Edit : Disclaimer I know this is on the homework forum but I need to tell you this homework is graded. I am sorry if I should not post this if it has to be graded

My attempt at the solution

Uncertainty in x = 28E-12 m (Turn pm into m)

h=6.63E-34 (constant)

hbar=1.055`19E-34 (constant)

hbar/2 = 5.275986363E-35 (constant)

Since the formula is

(Uncertainty in x)*(Uncertainty in momentum in x) >= hbar/2

and that it is asking for the minimum uncertainty, therefor minimum amount of uncertainty would be when it is hbar/2

(Uncertainty in x)*(Uncertainty in momentum in x) = hbar/2

So to calculate uncertainty in momentum

(Uncertainty in momentum in x)= (hbar/2)/(Uncertainty in x)

The answer I got is 1.884280844E-24

However this is wrong.

The only thing I can think of is that I got my magnitudes wrong? 28 pm should be 28E-12 m correct?

Im terribly sorry. I know this should be a simple question but I cannot figure out what is wrong with my calculations.

Assistance would be much appreciated.

Thank you.

Edit : Disclaimer I know this is on the homework forum but I need to tell you this homework is graded. I am sorry if I should not post this if it has to be graded