## ch1 question 43

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

ami patel
Posts: 20
Joined: Thu Jul 27, 2017 3:00 am

### ch1 question 43

i know this topic isn't going to be on the test, but the question is

what is the minimum uncertainty in the speed of an electron confined to within a lead atom of diameter 350. pm? model the atom as a one-dimensional box with a length equal to the diameter of the actual atom.

Janine Chan 2K
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Joined: Fri Sep 29, 2017 7:04 am

### Re: ch1 question 43

I also had a question on this^
The solution manual uses a different character for Planck's constant, and it uses the equation ∆p∆x= h/2, whereas in lecture we learned the equation ∆p∆x=h/4pi.

JamesAntonios 1E
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Joined: Fri Sep 29, 2017 7:04 am

### Re: ch1 question 43

Set up the equation like this. The change in momentum times the change in position has to be greater than or equal to h/4pi. Momentum is mv of an electron. v is the unknown but you do know the position. So, plug in these numbers (9.110x10^-31 kg)(x m/s)(350.x10^-12 m)>/(6.626x10^-34 Js)/4pi. Solve this out and you should get the right answer.

Rita Dang 3D
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Joined: Fri Sep 29, 2017 7:07 am

### Re: ch1 question 43

The equation the solutions manual uses is the same thing as ∆p∆x=h/4pi. The "h" the solution manual uses in the equation ∆p∆x= "h"/2 represents h/2pi, which is the same thing as h/4pi if you multiply it out.

Charles Ang 1E
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### Re: ch1 question 43

I believe that the difference in symbol between Planck's constant and h=h/2pi is denoted by a serif near the peak of the h. So if you see the letter h, it might be safe to assume it refers to Planck's constant.

Laura Riccardelli
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Joined: Fri Sep 29, 2017 7:04 am

### Re: ch1 question 43

Will Lavelle ever use the "h" that stands for another value other then Planks constant that the solution manual uses in the equation?

Diego Zavala 2I
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### Re: ch1 question 43

h-bar represents $h/2\pi$
(Planck's constant divided by $2\pi$)

Caitlin Mispagel 1D
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Joined: Tue Oct 10, 2017 7:13 am

### Re: ch1 question 43

When doing this problem do we not have to take into account the diameter of the electron?

kaitlindaugherty3L
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### Re: ch1 question 43

So even though this is a homework question, we don't have to know how to do problems involving Schrodinger's equation for the upcoming test or for the midterm, correct? Or do we need to know the equation for one or the other/ both?