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Homework Help: Finding Penetration Depth in a finite well

  1. Apr 5, 2004 #1
    The problem is as follows:

    A 50-eV electron is trapped between negligible-width capacitors charged to 200V (each with an exit hole). How far does its wave function extend beyond the capacitors? I know the answer is 1.6 x 10^-11 m, but I cannot get to that.

    Any ideas?

  2. jcsd
  3. Apr 5, 2004 #2
    A person who is clever than you is only a few pages ahead in the manual, simply read the manual, so you won't have to ask twice....
  4. Apr 6, 2004 #3

    I am not sure if you were trying to come off as rude, but thats how it sure seems. By manual I assume you mean the text I am getting my problem from? If thats the case, I have read the chapter on my own, as well as looked over the section this problem is from several times and I can't get it. Supposing im not as clever as you, perhaps you could give me a useful hint, rather than condescend.


    I managed to come to the correct answer, though I am not sure why exactly my last step worked. Apparently I had to multiply the 200V, and the 50 eV by the elementary charge (e). I understand why I multiplied 50 eV by e, but can somene explain why I needed to multiply 200 V, by e? I think it has to do with 200 V being the potential difference across the capacitors, whereas I need the Potential Energy. I am not fresh on E&M, can someone verify that step as correct?

    Thank you,
    Last edited: Apr 6, 2004
  5. Apr 6, 2004 #4
    Jason, I too am new to PF, and meant no offence.

    Its not users like myself you have to be worried about, its the PF monitors.

    They don't mind if you show how you tried to solve a problem, everyone is willing to advise and assist....

    What are you studying and look it up myself, to see if I can find us an answer for us both.


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