Name:______________________________Class:__________________ Date:__________________
Assessment
Electrical Energy and Current
Teacher Notes and Answers
17 Electrical Energy and Current
CAPACITANCE
10. 4.4 102 J
Given
C = 2.2 103 F
1. b
2. c
3. c
4. c
5. a
6. d
7. d
8. b
9. Charges move from one plate of the
capacitor through the connecting wire to the
other plate until the two plates are no longer
charged.
V = 450 V
Solution
1
PEelectric = C (V ) 2 =
2
1
(2.210 3 F)(450 V) 2 =
2
1
(2.210 3 F)(2.0105 V 2 ) =
2
4.410 2 J
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Physics
1
Section Quizzes
Name:______________________________Class:__________________ Date:__________________
Assessment
Electrical Energy and Current
Section Quiz: Capacitance
Write the letter of the correct answer in the space provided.
_____ 1. What is capacitance?
a. the amount of charge stored on a conductor
b. the ability to store energy as separated charges
c. the ability to store charge on the plates of a capacitor
d. stored electrical energy
_____ 2. When a capacitor is connected to a source of potential difference,
charges accumulate on the plates of the capacitor. The accumulation of
charge stops when
a. the charge on one plate is equal to the charge on the other plate.
b. the charge on the capacitor becomes zero.
c. the potential difference between the plates is the same as the source.
d. there is a difference in the amount of charge on the two plates.
_____ 3. Capacitors are devices that store energy. The energy stored in a
capacitor is equal to the
a. charge on the plates of the capacitor.
b. capacitance of the capacitor.
c. work required to place the charge on the plates of the capacitor.
d. difference in potential energy between the plates of the capacitor.
_____ 4. How does the net charge on a charged capacitor differ from the net
charge on an uncharged capacitor?
a. The net charge on the charged capacitor is greater than on the
uncharged capacitor.
b. There is a net charge on the charged capacitor, but there is no net
charge on the uncharged capacitor.
c. The net charge on both capacitors is the same.
d. The charged capacitor has a greater positive charge than the
uncharged capacitor.
_____ 5. A material is sometimes placed between the plates of a capacitor to
increase the capacitance. What is this material called?
a. a dielectric
b. an amplifier
c. a conductor
d. a semiconductor
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Physics
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Section Quizzes
Name:______________________________Class:__________________ Date:__________________
Electrical Energy and Current continued
_____ 6. Which will increase the capacitance of a capacitor to four times its
previous value?
a. Double the area of both plates.
b. Increase the area of one plate to four times its previous value.
c. Reduce the plate spacing by one-half.
d. Double the area of both plates and reduce the plate spacing by onehalf.
_____ 7. The electrical energy stored in a capacitor is
a. directly proportional to the voltage across the capacitor.
b. inversely proportional to the capacitance of the capacitor.
c. proportional to the square of the voltage across the capacitor.
d. all of the above
_____ 8. Which will not increase the energy stored in a capacitor by a factor of
sixteen?
a. Increase the capacitance to sixteen times the value.
b. Increase the potential difference across the capacitor to sixteen times
its previous value.
c. Increase the potential difference across the capacitor to four times its
previous value.
d. Double the potential difference across the capacitor and increase the
capacitance by four times.
9. A capacitor is discharged by connecting its terminals with a conducting wire.
What happens when the capacitor is discharged?
_________________________________________________________________
_________________________________________________________________
10. A capacitor has a capacitance of 2200 F and is charged to a potential
difference of 450 V. How much electrical potential energy is stored in the
capacitor?
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Physics
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Section Quizzes