Re: Electric fields and points of stability

[Rick Tarara <rtarara@SAINTMARYS.EDU>]

----- Original Message -----
From: "John Mallinckrodt" <ajm@CSUPOMONA.EDU>
To: <PHYS-L@lists.nau.edu>
Sent: Monday, October 14, 2002 1:47 PM
Subject: Re: Electric fields and points of stability


> Indeed, I wonder if Rick T's sketch is for the case of four line
> charges rather than four point charges as it does not seem to
> properly indicate the four additional zeroes.  On the other hand it
> may be that it simply neglects to show the field lines that leave
> those zeroes headed toward the center of the square.
The way the generator works is how we explain field lines.  I place a
positive test charge at equally spaced (angularly) positions around each
charge and then using all the charges in place, calculate the path that the
test charge would move.  That is what is traced.  The number of initial
charge positions is fixed and may not be properly chosen in this example to
show all the details.  This is really designed just to introduce the idea of
field lines to the class.  The way the lines are drawn, one can actually
watch them being generated.  With today's really fast machines, it happens
pretty fast, but not too fast (yet) to see.

Rick

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Richard W. Tarara
Professor of Physics
Saint Mary's College
Notre Dame, Indiana
rtarara@saintmarys.edu
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This posting is the position of the writer, not that of SUNY-BSC, NAU or the AAPT.