Wednesday, February 25, 2009
Chat Session has begun. Please post your question here.
Let's try posting and responding to posts via comments here. If you have trouble with that, you could also try gchatting me at zacksc@gmail.com , and I will paste your question into a comment here and respond here. Everyone should feel free to respond to anyone else's question. Even if you are not sure you can say what you think a good approach might be.
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I'm waiting....
ReplyDeleteI'm still here. Anyone want to start things off with a question?
ReplyDeleteLast call. Maybe 15 minutes more...
ReplyDeleteOk. Well, anyway, there will be the regular help session on Thursday at 6:00 PM.
ReplyDeleteNot so frequently asked questions:
ReplyDeleteBased on various experiements (phenomenology) we have a sense that Ge is similar to Si. To try to understand why that might be, we can start be looking at the periodic table. Just seeing that Ge is "under" Si is not enough. What does that mean? How many electrons does Ge have? How many more than the nearest noble gas core? (What is the nearest noble gas core?) For Ge, and to try to understand Au, you can assume a filled d-shell which takes up exactly 10 electrons. How many valence electrons does that leave to consider??
Zack, what chapter can we reference for the homework?
ReplyDeleteI have a few questions!
ReplyDeletenumber 4 from the book work, what is meant by 60 ampere-hours? in (60A for 1h, 30A for 2h, and so on) does not make sense to me. please explain further.
ReplyDeletefrom the virtual quiz, I'm not sure about 1. b. when voltage is applied, I'm not entirely sure what the electrons are doing
ReplyDeletealso, when phosphorus is combined with Si, what happens to the conductivity? I'm not sure of what material they are when combined.
what makes something more conductive than something else?
what is a superconductor?
what determines whether an electron will remain localized or become non-localized?
RadPick -
ReplyDeleteProblem 8-4) 60 ampere-hours means that the battery can supply a current of 60A for 1 hour before needing to be recharged.
If it supplies a current of 30A, then it will last for 2 hours.
If it supplies a current of 15A, then it will last for 3 hours. etc...
virtual quiz: 1b). The question is mainly asking if electrons enter the electron sea only when a voltage is applied.
We don't need to consider what material a combination Si and P make, Zack mentions that we can think of one thing substituting for another.
Each type of solid has a property called "Electrical Conductivity" which determines how conductive it is. We don't need to worry about that in this course.
For superconductors try reading the first part of http://en.wikipedia.org/wiki/Superconductor
Whether or not an electron will remain localized is a very difficult question. The main idea for us to know is that an individual atom will try and reach a stable configuration that has the lowest possible kinetic energy. In general, when an electron becomes de-localized, it reduces it's kinetic energy.
Hope this helps!
-Eliot
Talking with people from this class who were in class, and going to the help section tonight at 6 PM, would probably be much more helpful than reading the book. Also, as Eliot suggested, feel free to use other references (google, wiki,...
ReplyDeleteActually one thing that will really help you from the book is the periodic table. To do the problems, you want to focus on electron counting, noble gas cores, valance electron issues, etc., as we discussed in class. (see also the post above (#5) on these problems.)
ReplyDelete