Download ELECTRIC FIELD

Electric Fields and Voltage
PRE-LAB
Add symbols for + and – charges at the points assuming the point closest to the upper left corner of each figure
is a positive charge (interpret the equipotential lines that are shown). Draw in the approximate field lines (with
arrows). Hint: a ball on a hill will roll perpendicular to contour lines.
Electric Fields and Voltage
Parts List
Part
Graphite
Paper
Quantity
1
Power
Supply
1
Multi-meter
1
Point
Electrodes
2
Line
Electrode
2
Fastening
parts
2 each
Base Board
1
Screw, Wing nut, Banana Plug adaptor
Part I- Web Based simulation.
Go to http://www.slcc.edu/schools/hum_sci/physics/tutor/2220/e_fields/java/ . Construct the charge systems
shown in your pre-lab and check your answers.
Part II- determination of equipotential and the field lines.

Using the master plate, make the necessary holes in the graphite paper for testing the three
configurations shown below.
CONFIGURATION I
CONFIGURATION II
1. Starting with Configuration I, place the graphite
paper on the baseboard and secure the two
electrodes following the diagram shown here.
CONFIGURATION III
Wing Nut
Electrode
Graphite paper
Baseboard
washer
Screw
2. Connect the right electrode to the ground terminal of the power supply and the left electrode to the
positive terminal of the power supply.
3. Turn on the power supply and with the digital multi-meter (in DC mode) connected across the power
supply, set the output voltage to 10 volts.
4. You will now generate data for the upper half of your graphite paper only. The computer will generate
data for the lower half of the paper.
5. Open the EXCEL datasheet and input all the data you will be measuring.
6. Connect the ground probe of the digital meter to the ground port of the power supply.
7. Place the positive probe of the digital meter on the horizontal line of Y=0 cm and note the voltage.
Search other points on that line until you can find a location with v=8.5 volts reading. Record the X
coordinate of that point in the page titled “CASE 1” of your datasheet. If you can’t find a 8.5 volts
potential point on Y=0 cm line, leave the cell blank.
8. Repeat the above procedure to find similar points of v=8.5 volts on the Y=1 cm, Y=2 cm, …. Up to Y=9
cm.
9. Repeat the above procedure for v=8, v=7, v=6, v=5, v=4, v=3 and v=1.5 volt points on each of the Y=0
cm to Y=9 cm lines. Record the X coordinates in the datasheet.
10. After turning off the power supply, remove the point electrode from the left side and replace it with the
line electrode (configuration II).
11. Repeat steps 5 through 8 for the following voltages: 9, 8, 7, 5, 3.5, 2.5 and 1.5 volts and record the X
coordinates in the table located in the sheet titled “CASE 2” of your datasheet.
12. Remove the right point electrode and replace it with another line electrode (configuration III).
13. Repeat steps 5 through 8 for the following voltages: 9, 8,6, 5, 3, 2 and 1 volts and record the X
coordinates in the table located in the sheet titled “CASE 3” of your datasheet.
14. Print all three graphs (one for each configuration) generated by EXCEL and by connecting the points,
show the equipotential lines.
15. Draw the field lines by generating curves that are perpendicular to the potential curves for each of the
data points.