Transcript Chapter 17 - WordPress.com

Chapter 17
Section 1 Electric Potential
Objectives
 Distinguish between electrical potential
energy, electric potential, and potential
difference.
 Solve problems involving electrical energy
and potential difference.
 Describe the energy conversions that occur in
a battery.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 1 Electric Potential
Electrical Potential Energy
 Electrical potential energy -energy
associated with a charge due to its position in
an electric field.
 Magnitude of charge in field plays a role!
ME = KE + PEgrav + PEelastic + PEelectric
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 1 Electric Potential
Electrical Potential Energy,
continued
 Electrical Potential Energy in a Uniform
Electric Field
PEelectric = –qEd
PE =electrical potential energy
q=charge
E=electric field strength
d=distance
- PE increases in – charge and decreases if + charge
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
PE Charge and Direction
+ charge
- Charge
Toward E
Lose pe -
Gain pe +
Opposite E
Gain pe +
Lose pe -
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 1 Electric Potential
Electrical Potential Energy
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Section 1 Electric Potential
Chapter 17
Potential Difference
 Electric Potential = work done against
electric force to move a test charge a distance
in an electric field.
 V=volts= J/C
PEelectric
V
q
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 1 Electric Potential
 Potential difference is a change in electric
potential.
PEelectric
V 
q
change in electric potential energy
potential difference 
electric charge
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 1 Electric Potential
Potential Difference
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Electric Potential
Chapter
17
The
potential
difference in a
uniform field varies with distance
from a reference point.
 Test charge quantity is irrelevant!
 Related to field strength only
 Potential Difference in a Uniform Electric Field
∆V = –Ed
∆V= potential difference
E=magnitude of the electric field
d=displacement
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 1 Electric Potential
Sample Problem
Potential Energy and Potential Difference
A charge moves a distance of 2.0 cm in the direction
of a uniform electric field whose magnitude is 215
N/C.As the charge moves, its electrical potential
energy decreases by 6.9  10-19 J. Find the charge on
the moving particle. What is the potential difference
between the two locations?
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 1 Electric Potential
Sample Problem, continued
Potential Energy and Potential Difference
Given:
∆PEelectric = –6.9  10–19 J
d = 0.020 m
E = 215 N/C
Unknown:
q=?
∆V = ?
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 1 Electric Potential
Sample Problem, continued
Potential Energy and Potential Difference
PEelectric = –qEd
PEelectric
(–6.9  10 J)
q–
–
Ed
(215 N/C)(0.020 m)
–19
q  1.6  10 –19 C
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 1 Electric Potential
Sample Problem, continued
Potential Energy and Potential Difference
V  – Ed  –(215 N/C)(0.020 m)
V  –4.3 V
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 1 Electric Potential
Potential Difference, continued
 At right, the electric
potential at point A
depends on the charge at
point B and the distance
r.
 An electric potential
exists at some point in an
electric field regardless
of whether there is a
charge at that point.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 1 Electric Potential
Superposition Principle and
Electric Potential
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 1 Electric Potential
 reference point for potential difference is
infinity.
 Equation is
q
V  kC
r
potential difference = Coulomb constant 
value of the point charge
distance to the point charge
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 2 Capacitance
Objectives
 Relate capacitance to the storage of
electrical potential energy in the form of
separated charges.
 Calculate the capacitance of various devices.
 Calculate the energy stored in a capacitor.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 2 Capacitance
`
 A capacitor stores electrical
potential energy.
 units for capacitance is the farad,
F = (C/V)
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 2 Capacitance
Capacitors and Charge Storage,
continued
Capacitance= charge/volts
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 2 Capacitance
Capacitance
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 2 Capacitance
Capacitance for a ParallelPlate Capacitor in a Vacuum
 Capacitance depends on size and material of
a capacitor.
 Ε=permitivity constant 8.85X10-12C2/N*m
 D= distance
 A=area
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 2 Capacitance
Capacitors and Charge Storage
 The material
between a
capacitor’s plates
can change its
capacitance.
 Computer chips in
essence act as 1
E6th tiny capacitors
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 2 Capacitance
Parallel-Plate Capacitor
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 2 Capacitance
Energy and Capacitors
 The potential energy stored in a charged
capacitor depends on the charge and the
potential difference between the capacitor’s
two plates.
 PE=1/2CV2
PEelectric
electrical potential energy =
1
1
 QV
2
(charge on one plate)(final potential difference
2
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Honors
C= ε̧ A/d
 Where ε = permitivity (from table)
 A=area
 D=distance of plates
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Summing up equations
K cq
W PE F ed
V 


 Ed
q
q
q
d
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 2 Capacitance
Sample Problem
Capacitance
A capacitor, connected to a 12 V battery, holds 36
µC of charge on each plate. What is the capacitance
of the capacitor? How much electrical potential
energy is stored in the capacitor?
Given:
Q = 36 µC = 3.6  10–5 C
∆V = 12 V
Unknown:
C=?
PEelectric = ?
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 2 Capacitance
Sample Problem, continued
Capacitance
To determine the capacitance, use the definition
of capacitance.
Q
3.6  10 –5 C
C

V
12 V
C  3.0  10 –6 F  3.0 µF
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 2 Capacitance
Sample Problem, continued
Capacitance
To determine the potential energy, use the
alternative form of the equation for the potential
energy of a charged capacitor:
1
PEelectric  C( V )2
2
1
PEelectric  (3.0  10 –6 F)(12 V)2
2
PEelectric  2.2  10 –4 J
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 3 Current and
Resistance
Objectives
 Describe the basic properties of electric current,
and solve problems relating current, charge, and
time.
 Distinguish between the drift speed of a charge
carrier and the average speed of the charge
carrier between collisions.
 Calculate resistance, current, and potential
difference by using the definition of resistance.
 Distinguish between ohmic and non-ohmic
materials, and learn what factors affect
resistance.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 3 Current and
Resistance
Current and Charge Movement
 Electric current =rate at which electric
charges pass through a circuit.
 I=current measured in amperes or (amps)
given area.
Q
I
t
electric current =
charge passing through a given area
time interval
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 3 Current and
Resistance
Conventional Current
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 3 Current and
Resistance
Drift Velocity
 Drift velocity is the
the net velocity of a
charge in an electric
field.
 Drift speeds are
small
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 3 Current and
Resistance
Ohm’s Law
 Resistance =opposition =to electric current .
 units =ohm (Ω) volt / ampere.
 R=Resistance
 V=volts
V
R
I
potential difference
resistance 
current
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 3 Current and
Resistance
Resistance to Current
 Ohmic materials=resistance is constant over a
range of voltage.
 not true for all materials.
 Resistance depends on
 length,
 cross-sectional area,
 temperature, and material.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 3 Current and
Resistance
Factors that Affect
Resistance
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 3 Current and
Resistance
Resistance to Current
 Resistors can be used to control the amount
of current in a conductor.
 Potentiometers (rheostats, variable resistors)
have variable resistance.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 4 Electric Power
Sources and Types of Current
 Batteries and generators supply energy to
charge carriers.
 Current can be direct or alternating.
 In direct current, charges move in a single
direction.
 In alternating current, the direction of charge
movement continually alternates.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 4 Electric Power
Energy Transfer
 Electric power is the rate of conversion of
electrical energy.
• Electric companies measure energy
consumed in kilowatt-hours. A kilowatt
hour is equal to 3600000 J.
• Electrical energy is transferred at high
voltage to minimize energy loss. Reduce
current increase pressure.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 4 Electric Power
Energy Transfer
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 4 Electric Power
Relating Kilowatt-Hours to
Joules
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice
1. What changes would take place if the
electron moved from point A to point B in
the uniform electric field?
A. The electron’s electrical potential energy
would increase; its electric potential would
increase.
B. The electron’s electrical potential energy
would increase; its electric potential would
decrease.
C. The electron’s electrical potential energy
would decrease; its electric potential would
decrease.
D. Neither the electron’s electrical
potential energy nor its electric potential
would change.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
1. What changes would take place if the
electron moved from point A to point B in
the uniform electric field?
A. The electron’s electrical potential energy
would increase; its electric potential would
increase.
B. The electron’s electrical potential energy
would increase; its electric potential would
decrease.
C. The electron’s electrical potential energy
would decrease; its electric potential would
decrease.
D. Neither the electron’s electrical
potential energy nor its electric potential
would change.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
2. What changes would take place if the
electron moved from point A to point C in
the uniform electric field?
F. The electron’s electrical potential energy
would increase; its electric potential would
increase.
G. The electron’s electrical potential energy
would increase; its electric potential would
decrease.
H. The electron’s electrical potential energy
would decrease; its electric potential would
decrease.
J. Neither the electron’s electrical potential
energy nor its electric potential would
change.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
2. What changes would take place if the
electron moved from point A to point C in
the uniform electric field?
F. The electron’s electrical potential energy
would increase; its electric potential would
increase.
G. The electron’s electrical potential energy
would increase; its electric potential would
decrease.
H. The electron’s electrical potential energy
would decrease; its electric potential would
decrease.
J. Neither the electron’s electrical potential
energy nor its electric potential would
change.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
Use the following passage to answer questions
3–4.
A proton (q = 1.6  10–19 C) moves 2.0  10–6 m
in the direction of an electric field that has a
magnitude of 2.0 N/C.
3. What is the change in the electrical potential
energy associated with the proton?
A. –6.4  10–25 J
B. –4.0  10–6 V
C. +6.4  10–25 J
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
Use the following passage to answer questions
3–4.
A proton (q = 1.6  10–19 C) moves 2.0  10–6 m
in the direction of an electric field that has a
magnitude of 2.0 N/C.
3. What is the change in the electrical potential
energy associated with the proton?
A. –6.4  10–25 J
B. –4.0  10–6 V
C. +6.4  10–25 J
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
Use the following passage to answer questions
3–4.
A proton (q = 1.6  10–19 C) moves 2.0  10–6 m
in the direction of an electric field that has a
magnitude of 2.0 N/C.
4. What is the potential difference between the
proton’s starting point and ending point?
F. –6.4  10–25 J
G. –4.0  10–6 V
H. +6.4  10–25 J
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
Use the following passage to answer questions
3–4.
A proton (q = 1.6  10–19 C) moves 2.0  10–6 m
in the direction of an electric field that has a
magnitude of 2.0 N/C.
4. What is the potential difference between the
proton’s starting point and ending point?
F. –6.4  10–25 J
G. –4.0  10–6 V
H. +6.4  10–25 J
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
5. If the negative terminal of a 12 V battery is
grounded, what is the potential of the
positive terminal?
A. –12 V
B. +0 V
C. +6 V
D. +12 V
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
5. If the negative terminal of a 12 V battery is
grounded, what is the potential of the
positive terminal?
A. –12 V
B. +0 V
C. +6 V
D. +12 V
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
6. If the area of the plates of a parallel-plate
capacitor is doubled while the spacing
between the plates is halved, how is the
capacitance affected?
F. C is doubled
G. C is increased by four times
H. C is decreased by 1/4
J. C does not change
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
6. If the area of the plates of a parallel-plate
capacitor is doubled while the spacing
between the plates is halved, how is the
capacitance affected?
F. C is doubled
G. C is increased by four times
H. C is decreased by 1/4
J. C does not change
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
Use the following passage to answer questions
7–8.
A potential difference of 10.0 V exists across
the plates of a capacitor when the charge on
each plate is 40.0 µC.
7. What is the capacitance of the capacitor?
A. 2.00  10–4 F
B. 4.00  10–4 F
C. 2.00  10–6 F
D. 4.00  10–6 F
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
Use the following passage to answer questions
7–8.
A potential difference of 10.0 V exists across
the plates of a capacitor when the charge on
each plate is 40.0 µC.
7. What is the capacitance of the capacitor?
A. 2.00  10–4 F
B. 4.00  10–4 F
C. 2.00  10–6 F
D. 4.00  10–6 F
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
Use the following passage to answer questions
7–8.
A potential difference of 10.0 V exists across
the plates of a capacitor when the charge on
each plate is 40.0 µC.
8. How much electrical potential energy is
stored in the capacitor?
F. 2.00  10–4 J
G. 4.00  10–4 J
H. 2.00  10–6 J
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
Use the following passage to answer questions
7–8.
A potential difference of 10.0 V exists across
the plates of a capacitor when the charge on
each plate is 40.0 µC.
8. How much electrical potential energy is
stored in the capacitor?
F. 2.00  10–4 J
G. 4.00  10–4 J
H. 2.00  10–6 J
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
9. How long does it take 5.0 C of charge to pass
through a given cross section of a copper wire
if I = 5.0 A?
A. 0.20 s
B. 1.0 s
C. 5.0 s
D. 25 s
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
9. How long does it take 5.0 C of charge to pass
through a given cross section of a copper wire
if I = 5.0 A?
A. 0.20 s
B. 1.0 s
C. 5.0 s
D. 25 s
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
10. A potential difference of 12 V produces a
current of 0.40 A in a piece of copper wire.
What is the resistance of the wire?
F. 4.8 Ω
G. 12 Ω
H. 30 Ω
J. 36 Ω
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
10. A potential difference of 12 V produces a
current of 0.40 A in a piece of copper wire.
What is the resistance of the wire?
F. 4.8 Ω
G. 12 Ω
H. 30 Ω
J. 36 Ω
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
11. How many joules of energy are dissipated
by a 50.0 W light bulb in 2.00 s?
A. 25.0 J
B. 50.0 J
C. 100 J
D. 200 J
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
11. How many joules of energy are dissipated
by a 50.0 W light bulb in 2.00 s?
A. 25.0 J
B. 50.0 J
C. 100 J
D. 200 J
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
12. How much power is needed to operate a
radio that draws 7.0 A of current when a
potential difference of 115 V is applied across
it?
F. 6.1  10–2 W
G. 2.3  100 W
H. 1.6  101 W
J. 8.0  102 W
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Multiple Choice, continued
12. How much power is needed to operate a
radio that draws 7.0 A of current when a
potential difference of 115 V is applied across
it?
F. 6.1  10–2 W
G. 2.3  100 W
H. 1.6  101 W
J. 8.0  102 W
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Short Response
13. Electrons are moving from left to right in a
wire. No other charged particles are moving
in the wire. In what direction is the
conventional current?
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Short Response, continued
13. Electrons are moving from left to right in a
wire. No other charged particles are moving
in the wire. In what direction is the
conventional current?
Answer: right to left
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Short Response, continued
14. What is drift velocity, and how does it
compare with the speed at which an electric
field travels through a wire?
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Short Response, continued
14. What is drift velocity, and how does it
compare with the speed at which an electric
field travels through a wire?
Answer: Drift velocity is the net velocity of a
charge carrier moving in an electric field. Drift
velocities in a wire are typically much smaller
than the speeds at which changes in the
electric field propagate through the wire.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Short Response, continued
15. List four factors that can affect the
resistance of a wire.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Short Response, continued
15. List four factors that can affect the
resistance of a wire.
Answer: length, cross-sectional area
(thickness), temperature, and material
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Extended Response
16. A parallel-plate capacitor is made of two
circular plates, each of which has a diameter
of 2.50  10–3 m. The plates of the capacitor
are separated by a space of 1.40  10–4 m.
a. Assuming that the capacitor is operating in a
vacuum and that the permittivity of a vacuum
(e0 = 8.85  10–12 C2/N•m2) can be used,
determine the capacitance of the capacitor.
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Extended Response, continued
16. A parallel-plate capacitor is made of two
circular plates, each of which has a diameter
of 2.50  10–3 m. The plates of the capacitor
are separated by a space of 1.40  10–4 m.
a. Assuming that the capacitor is operating in a
vacuum and that the permittivity of a vacuum
(e0 = 8.85  10–12 C2/N•m2) can be used,
determine the capacitance of the capacitor.
Answer: 3.10  10–13 F
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Extended Response, continued
16. A parallel-plate capacitor is made of two
circular plates, each of which has a diameter
of 2.50  10–3 m. The plates of the capacitor
are separated by a space of 1.40  10–4 m.
b. How much charge will be stored on each
plate of the capacitor when the capacitor’s
plates are connected across a potential
difference of 0.12 V?
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Extended Response, continued
16. A parallel-plate capacitor is made of two
circular plates, each of which has a diameter
of 2.50  10–3 m. The plates of the capacitor
are separated by a space of 1.40  10–4 m.
b. How much charge will be stored on each
plate of the capacitor when the capacitor’s
plates are connected across a potential
difference of 0.12 V?
Answer: 3.7  10–14 C
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Extended Response, continued
16. A parallel-plate capacitor is made of two
circular plates, each of which has a diameter
of 2.50  10–3 m. The plates of the capacitor
are separated by a space of 1.40  10–4 m.
c. What is the electrical potential energy stored
in the capacitor when fully charged by the
potential difference of 0.12 V?
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Extended Response, continued
16. A parallel-plate capacitor is made of two
circular plates, each of which has a diameter
of 2.50  10–3 m. The plates of the capacitor
are separated by a space of 1.40  10–4 m.
c. What is the electrical potential energy stored
in the capacitor when fully charged by the
potential difference of 0.12 V?
Answer: 2.2  10–15 J
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Extended Response, continued
16. A parallel-plate capacitor is made of two
circular plates, each of which has a diameter
of 2.50  10–3 m. The plates of the capacitor
are separated by a space of 1.40  10–4 m.
d. What is the potential difference between a
point midway between the plates and a point
that is 1.10  10–4 m from one of the plates?
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Extended Response, continued
16. A parallel-plate capacitor is made of two
circular plates, each of which has a diameter
of 2.50  10–3 m. The plates of the capacitor
are separated by a space of 1.40  10–4 m.
d. What is the potential difference between a
point midway between the plates and a point
that is 1.10  10–4 m from one of the plates?
Answer: 3.4  10–2 V
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Extended Response, continued
16. A parallel-plate capacitor is made of two
circular plates, each of which has a diameter
of 2.50  10–3 m. The plates of the capacitor
are separated by a space of 1.40  10–4 m.
e. If the potential difference of 0.12 V is
removed from the circuit and the circuit is
allowed to discharge until the charge on the
plates has decreased to 70.7 percent of its
fully charged value, what will the potential
difference across the capacitor be?
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Standardized Test Prep
Extended Response, continued
16. A parallel-plate capacitor is made of two
circular plates, each of which has a diameter
of 2.50  10–3 m. The plates of the capacitor
are separated by a space of 1.40  10–4 m.
e. If the potential difference of 0.12 V is
removed from the circuit and the circuit is
allowed to discharge until the charge on the
plates has decreased to 70.7 percent of its
fully charged value, what will the potential
difference across the capacitor be?
Chapter menu
–2
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 2 Capacitance
Charging a Capacitor
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 2 Capacitance
A Capacitor With a
Dielectric
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 17
Section 2 Capacitance
Factors That Affect
Resistance
Chapter menu
Resources
Copyright © by Holt, Rinehart and Winston. All rights reserved.