Teacher’s Signature:___________
Date: _____________________
Physics Laboratory
United International University
Name: _______________________________________ ID: ______________
Section: _____ Group: _______Trimester: ___________ Date:
___________
Experiment No. 06
Determination of capacitance and stored energy by constructing a parallel
plate capacitor with variable dielectric materials
Theory: The capacitance of a given capacitor is defined as the ratio of the magnitude of the
charge (on either one of the conductors), q, to the voltage (potential difference), V, applied
across the two conductors, thus:
or
Capacitance is a measure of the amount of net or excess charge on either one of the
conductors per unit potential difference. The more charge a capacitor can store at a given
voltage, the larger the capacitance.
The actual mathematical expression for the capacitance of a parallel plate capacitor of plate
area, A, plate separation d, and ε is the dielectric permittivity of a particular medium,
The stored energy can be calculated using the formula
Here, V is the potential difference between the two parallel plate
capacitor.
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Physics Laboratory
Apparatus:
Dielectric constant kit 1, Electrometer amplifier 1, Digital multimeter 1, Power supply ( 2-12
V AC/DC) 1, High voltage power supply (0-600V DC) 1, Flexible plug leads (50 cm), black
2, Flexible plug leads (50 cm), red 2, Earthing lead (100 cm), green 1, 2 way switch 1,
Capacitor module 0.01mF 1, Capacitor module 100nF 1, 4.7 MW Resistance box 1, Flexible
plug leads (25 cm), black 2, Flexible plug leads (25 cm), red 2, Flexible plug leads (50 cm),
yellow 3, Flexible plug leads (100 cm), red & black 1
Experimental Data:
The Area, A=
Separation, d =
Capacitance of reference capacitor, C =
Dielectric
Material
Vacuum
Teflon
Glass
Voltage
difference
between
the plates,
V
0.5
1
1.5
0.5
1
1.5
0.5
1
1.5
Capacitance
Capacitance
Calculated
(Experimental Value)
Stored
energy,
Calculated
Calculation: (i) Error and Accuracy for Capacitance measurement :
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Stored energy,
Experimental
Physics Laboratory
Difference (%) =
=
=
=
=
Accuracy (%) = 100% - % Difference =
(ii) Error and Accuracy for Stored Energy measurement :
Difference (%) =
Accuracy (%) = 100% - % Difference =
Result:
The measured capacitance, C=
The measured stored energy, U=
……………………………………dielectric material will be the best option for energy storage.
Discussions:
Q: How can you further increase the stored energy by keeping the dielectric material constant?
Q: Plot a graph of applied voltage V vs stored energy U for the capacitors with different dielectric materials.
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Physics Laboratory
Q: Do you think the environmental temperature can affect the energy storage process of the capacitor?
Q: Write five real life applications where capacitors have been used in energy storage.
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