Physics
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Lab 5: Capacitors
Objectives In this lab you will use PhET’s simulation Capacitor Lab: Basics to study capacitors. More
specifically you will use the Capacitance simulation for all parts.
Part 1: Dependence of Capacitance on Plate Area Make sure you are using the Capacitance simulation.
1. Check the boxes for: “Bar Graphs” and “Capacitance”.
2. Disconnect the capacitor from the battery as shown in the figure above.
3. Set the separation of the plates to 6.0 mm. Do not change the separation of the plates in this
part.
4. Change the plate area and record the corresponding capacitance.
5. Complete the following table.
Plate Area (mm2) 100 150 200 250 300 350 400
Capacitance (pF)
6. Using Excel, graph a scatter plot of capacitance versus plate area. Graph capacitance on the
vertical axis and plate area on the horizontal axis. Include the best-fit curve on your graph
as well as the equation of the best-fit curve. Decide the type of curve to fit the data with
based on theoretical expectation.
7. Are your results as expected from theory?
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Part 2: Dependence of Capacitance on Separation of Plates Make sure you are using the Capacitance simulation.
1. Continue with the same setup of the previous part (see the figure in part 1).
2. Set the plate area to 400 mm2. Do not change the plate area in this part.
3. Change the separation of the plates and record the corresponding capacitance.
4. Complete the following table.
Separation (mm) 2 3 4 5 6 7 8 9 10
Capacitance (pF)
5. Using Excel, graph a scatter plot of capacitance versus separation. Graph capacitance on the
vertical axis and separation on the horizontal axis. Include the best-fit curve on your graph
as well as the equation of the best-fit curve. Decide the type of curve to fit the data with
based on theoretical expectation.
6. Are your results as expected from theory?
Part 3: Charged Capacitor Make sure you are using the Capacitance simulation.
1. Check the boxes for: “Plate Charges”, “Bar Graphs”, “Capacitance”, “Top Plate Charge”, and
“Stored Energy”.
2. Make sure the capacitor is connected to the battery.
3. Use the voltmeter to measure the applied voltage.
4. Set the separation of the plates to 6.0 mm and the plate area to 200 mm2. This gives a
capacitance of 0.30 pF. Do not change the plate separation and the plate area in this part.
5. Change the applied voltage (by moving the slider on the battery up) and record the corresponding plate charge.
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6. Complete the following table.
Applied Voltage (V) 0 0.25 0.5 0.75 1 1.25 1.5
Plate Charge (pC)
Stored Energy (pJ)
7. Using Excel, graph a scatter plot of plate charge versus applied voltage. Graph plate charge
on the vertical axis and applied voltage on the horizontal axis. Include the best-fit curve on your graph as well as the equation of the best-fit curve. Decide the type of curve to fit the
data with based on theoretical expectation.
8. Using Excel, graph a scatter plot of stored energy versus plate charge. Graph stored energy
on the vertical axis and plate charge on the horizontal axis. Include the best-fit curve on
your graph as well as the equation of the best-fit curve. Decide the type of curve to fit the
data with based on theoretical expectation.
9. Are your results as expected from theory?