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Potential Plotting

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Lab Activities

Students experimentally plot the equipotential lines and electric field lines for a variety of charge configurations. Common configurations include:

  • two parallel lines

  • two concentric circles

  • a circle between two parallel lines

  • a pear shape near a straight line

  • a shape of the students choosing which includes a sharp point and a straight line.

The charge configurations are made using conducting ink on grid lined carbon paper. The ink shapes are charged by connecting them to the terminals of a DC power supply. The equipotentials are plotted using two test leads connected to a multimeter. One of the test leads is kept in one location while the student moves the other test lead and marks the locations where the voltage between the two leads is zero. The field lines are plotted by using a rubber band to join the test leads together. Keeping one of the leads stationary, the leads are rotated until the voltage on the multimeter is at a maximum showing the direction of the electric field at that point.

Course Level

Introductory: P4, P14, P16

Student Handouts


Number of set-ups available: 20

Per lab station:

1 corkboard
5 sheets of conducting paper
6 pushpins
1 DC power supply
1 multimeter
1 conducting fluid pen
2 black banana leads
2 probes (1 black; 1 red)
2 wires/metal eye connector
1 circle template
1 poster board circular template
2 rubber bands
1 hazardous materials MSDS warning sheet
1 pair of pliers

Charges apparatus


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Site contact: largent@Dartmouth.EDU

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