Download 1. The units of potential difference are A. J B. J/C C. V/m D. N/C

1. The units of potential difference are
A.
B.
C.
D.
J
J/C
V/m
N/C
© 2010 Pearson Education, Inc.
Answer
1. The units of potential difference are
A.
B.
C.
D.
J
J/C
V/m
N/C
© 2010 Pearson Education, Inc.
2. What are the units of the electric field?
A.
B.
C.
D.
E.
V/C
N/C
V/m
J/C
Ω/m
© 2010 Pearson Education, Inc.
Answer
2. What are the units of the electric field?
A.
B.
C.
D.
E.
V/C
N/C
V/m
J/C
Ω/m
© 2010 Pearson Education, Inc.
3. The electric potential inside a parallel-plate
capacitor
A. is constant.
B. increases linearly from the negative to the
positive plate.
C. decreases linearly from the negative to the
positive plate.
D. decreases inversely with distance from the
negative plate.
E. decreases inversely with the square of the
distance from the negative plate.
© 2010 Pearson Education, Inc.
Answer
3. The electric potential inside a parallel-plate
capacitor
A. is constant.
B. increases linearly from the negative to
the positive plate.
C. decreases linearly from the negative to the
positive plate.
D. decreases inversely with distance from the
negative plate.
E. decreases inversely with the square of the
distance from the negative plate.
© 2010 Pearson Education, Inc.
4. The electric field
A. is always perpendicular to an equipotential
surface.
B. is always tangent to an equipotential
surface.
C. always bisects an equipotential surface.
D. makes an angle to an equipotential surface
that depends on the amount of charge.
© 2010 Pearson Education, Inc.
Answer
4. The electric field
A. is always perpendicular to an
equipotential surface.
B. is always tangent to an equipotential
surface.
C. always bisects an equipotential surface.
D. makes an angle to an equipotential surface
that depends on the amount of charge.
© 2010 Pearson Education, Inc.
Example Problem
Is the change in potential energy, ∆U, of a positive
particle increasing, decreasing, or staying the
same as it moves from points i to f?
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Conceptual Example Problem
Rank in order, from largest to smallest, the
electric potentials at the numbered points.
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Potential and Field for Three Important Cases
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The Capacitance of a Parallel-Plate Capacitor
Q = C DVC
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What are capacitors good for?
Store Energy
That can be quickly
released
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Energy stored in a Capacitor
UC = QDVaverage
What would Vaverage be?
DVaverage is 0 + DV = ½ DV
UC = ½ QDVC
© 2010 Pearson Education, Inc.
Q = C DVC
Energy stored in a Capacitor
UC = ½ QDVC
Plug in
Q = C DVC
UC = ½ C(DVC)2
UC = ½ QDVC = ½ C(DVC)2 = ½ Q2/C
© 2010 Pearson Education, Inc.