Physics 230 February 13 2002
Exercise on analyzing the result of a calculation.
In class we obtained the electric field produced by a sheet of charge lying in
plane, with charge density
that is infinitely long in the
and extends from
the electric field is given
Now we want to analyze this result.
1. Dimensions. The angle is just a number with no units The charge density has dimensions of charge/length and so the electric field is charge/length and these are the correct dimensions.
2. Check the result a large distance from the strip.
At a great distance
from the strip, the strip looks like a line charge with line charge density
Thus we should find (Example 24.2)
In our expression,
3. Check the result very close to the strip. For
the strip "looks" infinitely wide, and so we should obtain the result of
In our expression, with
The result passes all three checks and so is probably correct.This document created by Scientific WorkPlace 4.0.