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%(DRAFT Milica Markovic Summer 2004) % text you want to see
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\begin{document}
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\noindent
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\centerline{\Large{EEE161 Applied Electromagnetics Laboratory 6}}
\vspace{0.3cm}
\noindent
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\noindent
\centerline{Instructor: Dr. Milica Markovi{\'c}} \\
\centerline{Office: Riverside Hall 3028} \\
\centerline{Email: } \\
\centerline{Web:
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\begin{description}
\item{\bf{Part 1}}
Solve the following problem on paper. Do not attempt to solve the integral. Find the potenital due to a ring of charge everywhere around the ring. The ring is charged with a line charge density of $\rho_l$\,nC/m.
\item{\bf{Part 2}}
Use the code below to plot the potential of a ring of charge
\begin{verbatim}
clearall
%Specify the extents of x,y,z axes
rad=-1.5:0.1:1.5
%Make X,Y,Z matrices
[X Y Z]=meshgrid(rad,rad,rad)
%Define constants epsilon, Q. They are obviously not physical. They are set
%to small constants so that we get smaller numbers.
eps=1
Q=1
const=Q/(2*pi*eps)
%Set the initial potential value to zero. Initialize V.
V=0
%Here we find the potential at all X,Y,Z points defined previously from
%each of the "unit" charges on the ring. The th variable starts from 0.1
%to avoid the infinite value of V at the point r=1,theta=0.
forth=0.1:pi/20:2*pi
t=const./sqrt((X-cos(th)).^2 + (Y-sin(th)).^2 + (Z).^2)
V= V+t;
end
%Plot the volume distribution of potential at planes x=0, y=0, z=0
slice(X,Y,Z,V,[0],[0],[0])
%Keep the same figure
holdon;
%Plot contours of potential at planes x=0, y=0, z=0
h=contourslice(X,Y,Z,V,[0],[0],[0])
set(h,'EdgeColor','k','LineWidth',1.5)
\end{verbatim}
\item{\bf{Part 3}}
Plot several equipotential surfaces using the code below.
\begin{verbatim}
clearall
%Specify the extents of x,y,z axes
rad=-1.5:0.1:1.5
%Make X,Y,Z matrices
[X Y Z]=meshgrid(rad,rad,rad)
%Define constants epsilon, Q. They are obviously not physical. They are set
%to small constants so that we get smaller numbers.
eps=1
Q=1
const=Q/(2*pi*eps)
%Set the initial potential value to zero. Initialize V.
V=0
%Here we find the potential at all X,Y,Z points defined previously from
%each of the "unit" charges on the ring. The th variable starts from 0.1
%to avoid the infinite value of V at the point r=1,theta=0.
forth=0.1:pi/20:2*pi
t=const./sqrt((X-cos(th)).^2 + (Y-sin(th)).^2 + (Z).^2)
V= V+t;
end
%Plot the volume distribution of potential at planes x=0, y=0, z=0
p = patch(isosurface(X,Y,Z,V,7));
isonormals(X,Y,Z,V,p)
set(p,'FaceColor','red','EdgeColor','none');
daspect([1 1 1])
view(3); axis tight
camlight
lightinggouraud
\end{verbatim}
\item{\bf{Part 4}}
Solve the following problem on paper. Do not attempt to solve the integral. Find the electric field due to a ring of charge everywhere around the ring. The ring is charged with a line charge density of $\rho_l$\,nC/m.
\item{\bf{Part 5}}
Write a code to plot the electric field due to ring with a line charge distribution $\rho_l$. To solve this problem replace the integral with a finite sum. You can modify the example for the potential to find the electric field. Remember that the electric field is the negative gradient of the potential.
\begin{figure}[htbp]
\begin{center}
\strut\psfig{figure=../fig/chargedistribution.ps,width=8cm} \\
\end{center}
\caption{Part 1}
\label{meshgrid}
\end{figure}
\item{\bf{Conclusion}}
Solve {\bf all of the above examples by hand} and {\bf compare} the results with the ones you found during the lab. In addition, for each of the problems, write what you have learned. Do not write an essay, just in a few sentences write what you have done in each problem, and specifically what you have learned from the work done.
\item{\bf{Due Date}}
Submit the printout of the lab work and the conclusion by NEXT FRIDAY. LAB IS DUE next Friday in the lab. No late labs.
\end{description}
\end{document}
\bye