Go to http://phet.colorado.edu/simulations/sims.php?sim=Charges_and_Fields and click on Run Now.
Part 1: What is an equipotential line and how is this simulation related to work and energy?
1) Turn on “Show Numbers”
2) Place a positive 1 nano-coulomb charge near the center of the screen.
3) In the lower left of the screen is a meter for indicating electric potential, in volts, created by the charge that you introduced. Record the voltage and turn on “Plot”.
4) This line is much like a line on a geologic topo map. Explain the similarity.
In a topo map it shows all the elevation points as a higher or lower surface focusing on the lowest and highest point. If you imagine that the Nc puck is that highest or lowest point then the area around it will become lower or higher in voltage (depending on the charge of the puck) so think of voltage as elevation.
5) would be doing no work on your You are on the side of a hill with a topo map of the region. If you walked so that your trip follows a topo line you backpack. Why?.
If following a topo line there would be no changes in elevation. Which means you would not be fighting gravity and gravity would not be fighting you so no work is done.
6) If a second charge were placed on this line (don’t do it), how much work is need to move it along the line?
The work done moving along the line is zero. The potential work is defined as it equal to the minus the work done and it doesn’t change.
7) Move the meter closer to the charge at the center of the screen. What is the new electric potential? Turn on plot again
It moved to 9.2 V
8) Remember that electric potential is energy per charge (1 volt = 1 Joule/Coulomb). Is electric potential a vector or a scalar?
Its Scalar
9) If a second positive charge were introduced and moved from the first equipotential line created to the second line (closer to the charge),