% Work in progress
% I have decided to incorporate the procedure into the Ohm's law lab in the Lab
% manual; so, I have an online version, while keeping the original version.
%
\documentclass{article}
\usepackage{p122l-lds}
\usepackage{clc_units}
\SETPAGE{2}{Coulomb's Law}

\begin{document}
\LABTITLE{\LABNAME}
\TeamMembers
\GenearalInstructions

\newcommand{\RULE}{\makebox[0.75in]{\hrulefill}}
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%\section*{\RDS}
%\TeamMembers
%\vspace{-0.2in}
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%----------------------------------------------------------------
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\normalsize
\noindent
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% \section*{Based on a PHET simulation}
Open this PHET simulation 
\begin{verbatim}
https://phet.colorado.edu/sims/html/circuit-construction-kit-dc-virtual-lab/latest/circuit-construction-kit-dc-virtual-lab_en.html
\end{verbatim}
in your browser. 

Form the left-hand menu, you can pick resistors, batteries and wire; from the items
on the left you can get ammeters and voltmeters. Note that you can set the values
of the resistor and battery by clicking on them, and then selecting the desired value 
from the slider bar that appear at the bottom of the screen. To connect two elements,
bring one of their ends into contact; to separate them, click on their junction, and 
then on the scissors that appear on the screen; To remove elements form the screen, 
first detach them from other elements, and then return them to their original bins.

By default the simulation shows the motion of the electrons
in the circuit. However, we are going to use the conventional view, that
shows how positive charge moves in the circuit; in this view, the charge moves from 
higher to lower potential. We are also assuming that wires and batteries have 
no resistance.


%
\section*{Common Resistor}
In this part of the lab, we explore the relationship between voltage across 
and current through a single resistor. 


\section*{Procedure}
Obtain a resistor, a battery, and some wire to build a circuit that connects the 
battery and the resistor. 

To measure how much current is passing through the resistor, you need to connect an
 ammeter in series with the resistor; to measure the voltage drop across the 
resistor, you need to connect a voltmeter in parallel with the resistor.

Set the resistor value to 1 \UOhm\ and the battery to 2 \UV . 
Keep the value of the resistor fix, but vary the battery's voltage from 2 to 12 \UV
in increments of 2 \UV.


Change the value of the resistor to 50 \UOhm and keep it constant as you change the
battery's voltage from 2 to 12 \UV in increments of 2 \UV. 

\section*{Data}
Make a table to record the current through this resistor, and the voltage across it; 
Record your results in another table.

\section*{Analysis}
\begin{enumerate}
\item 
Use graph paper to Plot the data from both resistors; use the vertical axis for 
the voltage and the horizontal axis for the current. Use a different symbol type
to distinguish the data from each resistor. 

\vspace{2in} \mbox{} \\
\item 
If the data plotted  looks like straight lines, use a straight edge to 
determine, and draw the best fit line for each of the resistors;
\item 
Determine the slope of both best fit lines. 
\item What is the relationship between the slope of the best fit lines and Ohm's Law.
\item  Compare, by percent difference, the value of the slope of the best fit line and the value of the corresponding resistor.
\item for a given change in voltage, which resistor gives the larges change in current?
\end{enumerate}

%
\newpage
\section*{Electric Force and Charge}
In this experiment, we control the amount of electric charge and observe the force between them.

\section*{Data}
Place a 1 \Umicro\UC\ positive charge at the 0 centimeter mark of the meter scale.
Place another 1 \Umicro\UC\ positive charge at the second centimeter mark of the meter scale.
Record the force on $q_1$ in Newtons and the charge on each charge in Coulombs (use scientific notation).
Next, increase the amount of charge on each sphere by the same amount; make the increases successively 
to 2, 3, 4, 5, 6, 7, and 8 Coulombs. 
Make a table with the charge on each sphere on the first column and the force on $q_1$ on the second column.
include a third column on your data table to include the product of the charges $q_1$ and $q_2$, call this variable $x$.

%
\section*{Analysis}
\begin{enumerate}
\item 
Use graph paper to Plot the force on $q_1$ as a function of x. 
Call this Figure 3 and included it as an appendix to this document.
\item 
If the data on Figure 3 look like a straight line, use a straight edge to determine the line that best fit your data.
Draw the best fit line  on top of your data in Figure 3.
\item Determine the slope of the best fit line. 
\item What is the relationship between the slope of this best fit line and Coulomb's Law;
\item From the results and your data of this section, estimate the permeability of free space.

\end{enumerate}
%
\section{Questions}
\begin{enumerate}
\item How your estimates for the permeability of free space, compare with its accepted value.
\end{enumerate}
\end{document}
