
Ignatios Vakalis
Department of Mathematics and Computer Science
Capital University
East Main Street
Columbus OH 43209
ivakalis@capital.edu
Electrostatic Potential Due to Continuous 1-D Charge
This project (module) presents the problem of computing the electrostatic
potential at a specific point, due to a continuous charge distribution. Such
a problem involves: modeling, analysis and symbolic/numeric/graphical calculations.
Computer Algebra Systems (Maple/Mathematica) as well as procedural languages
(Fortran/C) are used so that a student would appreciate the power and limitations
of various numeric and symbolic methods.
The entire module is of hypertext nature and includes interactive code for
both Maple and Mathematica. The interactivity (ability to open a
Maple/Mathematica window with a click of a button and execute a session of
commands) offered in this module allows greater experimentation (with a CAS)
and ease of use.
Two versions of the "electrostatic potential" problem are explored:
-
1-D Finite Length Wire: A charged wire resides on the y-axis on the
interval [-1, 1]. The problem of formulating and solving a model for
calculating the potential at a given point is presented. A discrete model
is developed and Maple/Mathematica are used to obtain its solution. A
continuous model is also derived expressing the potential as an 1-D
integral. Fortran/C implementations of the Trapezoidal and Simpson's
rules are used as one way of solving the continuous model. Maple/Mathematica
explorations lead to symbolic and numeric solutions of the model as well
as to the derivation of the "error term" involved in the development of the
two elementary quadrature rules.
-
Infinite Length Wire: An extension of the previous case to an infinite
length wire is explored. A discussion of the limitations of the Trapezoidal
and Simpson's rule for this case is provided, and the power offered by a
CAS is employed in an attempt to find an exact or an approximate value
of the potential at a given point. A numerical integration routine, adopted
from NETLIB is provided, thus giving the user the chance to explore its power
and sophistication.
Thomas L. Marchioro
Jeffrey R. Christiansen
uces_info@krellinst.org
17 July, 1997