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QuickCheck 21.1
In physics, what is meant by the term “work”?
A.
B.
C.
D.
Force × distance.
Energy transformed from one kind to another.
Energy transferred into a system by pushing on it.
Potential energy gained or lost.
© 2015 Pearson Education, Inc.
Slide 21-1
QuickCheck 21.2
As a positive charge is moved from position i to position f,
is its change in electric potential energy positive (+),
negative (–), or zero (0)?
© 2015 Pearson Education, Inc.
1
2
3
4
A
0
+
+

B
0

+

C

+

+
D
+
+

0
Slide 21-2
QuickCheck 21.3
Two charges are brought separately into the vicinity of a fixed
charge +Q.
• First, +q is brought to
point A, a distance
r away.
• Second, +q is
removed and –q
is brought to the
same point A.
The electric potential at point A is:
A. Greater for the +q charge in situation 1.
B. Greater for the –q charge in situation 2.
C. The same for both.
© 2015 Pearson Education, Inc.
Slide 21-3
QuickCheck 21.4
Two charges are brought separately into the vicinity of a fixed
charge +Q.
• First, +q is brought to
point A, a distance
r away.
• Second, +q is
removed and –q
is brought to the
same point A.
The electric potential is:
A. Greater for the +q charge in situation 1.
B. Greater for the –q charge in situation 2.
C. The same for both.
© 2015 Pearson Education, Inc.
Slide 21-4
QuickCheck 21.5
A positive charge moves as shown. Its kinetic energy
A. Increases.
B. Remains constant.
C. Decreases.
© 2015 Pearson Education, Inc.
Slide 21-5
QuickCheck 21.6
A positive and a negative charge are
released from rest in vacuum. They
move toward each other. As they do:
A.
B.
C.
D.
E.
A positive potential energy becomes more positive.
A positive potential energy becomes less positive.
A negative potential energy becomes more negative.
A negative potential energy becomes less negative.
A positive potential energy becomes a negative potential
energy.
© 2015 Pearson Education, Inc.
Slide 21-6
QuickCheck 21.7
A proton is released from rest at the dot. Afterward, the
proton
A. Remains at the dot.
B. Moves upward with
steady speed.
C. Moves upward with
an increasing speed.
D. Moves downward with
a steady speed.
E. Moves downward with an increasing speed.
© 2015 Pearson Education, Inc.
Slide 21-7
QuickCheck 21.8
If a positive charge is released from rest, it moves in the
direction of
A.
B.
C.
D.
E.
A stronger electric field.
A weaker electric field.
Higher electric potential.
Lower electric potential.
Both B and D.
© 2015 Pearson Education, Inc.
Slide 21-8
QuickCheck 21.9
Two protons, one after the other,
are launched from point 1 with
the same speed. They follow the
two trajectories shown. The
protons’ speeds at points 2 and
3 are related by
A.
B.
C.
D.
v2 > v3
v2 = v3
v2 < v3
Not enough information to compare their speeds
© 2015 Pearson Education, Inc.
Slide 21-9
QuickCheck 21.10
A proton starts from rest at point A. It then accelerates past
point B.
The proton’s kinetic energy at Point B is
A.
B.
C.
D.
250 eV
200 eV
150 eV
100 eV
© 2015 Pearson Education, Inc.
Slide 21-10
QuickCheck 21.11
What is the ratio VB/VA of the electric potentials at the two
points?
A.
B.
C.
D.
E.
9
3
1/3
1/9
Undefined without knowing the charge
© 2015 Pearson Education, Inc.
Slide 21-11
QuickCheck 21.12
What is the electric potential at the surface of the sphere?
A.
B.
C.
D.
E.
15 V
30 V
60 V
90 V
120 V
© 2015 Pearson Education, Inc.
15 cm
R = 5 cm
V = 30 V
Slide 21-12
QuickCheck 21.13
An electron follows the trajectory shown from point 1 to
point 2. At point 2,
A.
B.
C.
D.
v2 > v1
v2 = v1
v2 < v1
Not enough information to compare the speeds at
these points
© 2015 Pearson Education, Inc.
Slide 21-13
QuickCheck 21.14
At the midpoint between these two equal but opposite
charges,
A.
B.
C.
D.
E.
E  0; V = 0
E  0; V > 0
E  0; V < 0
E points right; V = 0
E points left; V = 0
© 2015 Pearson Education, Inc.
Slide 21-14
QuickCheck 21.15
At which point or points is the electric potential zero?
A.
B.
C.
D.
E. More than one of these
© 2015 Pearson Education, Inc.
Slide 21-15
QuickCheck 21.16
Four charges lie on the corners of a square with sides of
length a. What is the electric potential at the center of the
square?
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Slide 21-16
QuickCheck 21.17
A particle follows the trajectory shown from initial position
i to final position f. The potential difference V is
A.
B.
C.
D.
E.
100 V
50 V
0V
–50 V
–100 V
© 2015 Pearson Education, Inc.
Slide 21-17
QuickCheck 21.18
Which set of equipotential
surfaces matches this electric
field?
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Slide 21-18
QuickCheck 21.19
Metal wires are attached
to the terminals of a 3 V
battery. What is the potential
difference between points
1 and 2?
A.
B.
C.
D.
E.
6V
3V
0V
Undefined
Not enough information
to tell
© 2015 Pearson Education, Inc.
Slide 21-19
QuickCheck 21.20
Metal spheres 1 and 2 are connected by a metal wire. What
quantities do spheres 1 and 2 have in common?
A.
B.
C.
D.
E.
Same potential
Same electric field
Same charge
Both A and B
Both A and C
© 2015 Pearson Education, Inc.
Slide 21-20
QuickCheck 21.21
What is the capacitance of these two electrodes?
A.
B.
C.
D.
E.
8 nF
4 nF
2 nF
1 nF
Some other value
© 2015 Pearson Education, Inc.
Slide 21-21
QuickCheck 21.22
A capacitor has a charge Q. The plates are then pulled apart
so that the distance between them is larger.
After the plates are pulled apart,
A.
B.
C.
D.
E.
The charge increases and the electric field decreases.
The charge decreases and the electric field increases.
Both the charge and the field increase.
Both the charge and the field decrease.
The charge and the field remain constant.
© 2015 Pearson Education, Inc.
Slide 21-22
QuickCheck 21.23
A capacitor is attached to a battery. The plates are then
pulled apart so that the distance between them is larger.
After the plates are pulled apart,
A.
B.
C.
D.
E.
The charge increases and the electric field decreases.
The charge decreases and the electric field increases.
Both the charge and the field increase.
Both the charge and the field decrease.
The charge and the field remain constant.
© 2015 Pearson Education, Inc.
Slide 21-23
QuickCheck 21.24
A capacitor charged to 1.5 V stores 2.0 mJ of energy. If the
capacitor is charged to 3.0 V, it will store
A.
B.
C.
D.
E.
1.0 mJ
2.0 mJ
4.0 mJ
6.0 mJ
8.0 mJ
© 2015 Pearson Education, Inc.
Slide 21-24