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Quiz Side (Solution on other side)
Phy 122: Quiz Electrical Potential Energy
Name ________________________
At the right is a diagram showing some equipotential lines
F
resulting from the charged surface shown and some lettered
locations (A-G).
E
G
D
a) Draw at least 5 Electric Field lines.
C
B
b) Is the shaded charged surface positive or negatively
charged? How do you know?
A
c) Find the location (A-G) where the Electric Field will be
greatest.
d) Is the work done by the electric field in moving a +3 µC
point charge from B to D, positive, negative, or zero?
Explain.
-100V
-75V
-50V
e) How much work is done by the electric field in moving a
+3 µC point charge from B to D? Explain.
f) Find a location (A-G) that is at a higher electrical potential than at D.
g) Find a location (A-G) that is at the same electrical potential as at D.
h) Find a location (A-G) where a positive test charge would have a higher
electrical potential energy than at D.
i) Describe this region using the geographical analogy (topographical maps).
What will this region “look” like for a positive charge?
-25V
Solution Side
Phy 122: Quiz Electrical Potential Energy
Name ________________________
At the right is a diagram showing some equipotential lines
F
resulting from the charged surface shown and some lettered
locations (A-G).
E
G
D
a) Draw at least 5 Electric Field lines. Direction downhill and
C
perpendicular to the equipotential lines.
B
b) Is the shaded charged surface positive or negatively
charged? How do you know? Negative, see direction of
V values getting more negative
c) Find the location (A-G) where the Electric Field will be
greatest. A, ∆V/∆x is greater as V lines closer together.
A
-100V
-75V
d) Is the work done by the electric field in moving a +3 µC
point charge from B to D, positive, negative, or zero?
Explain. Negative as the force on the + test charge is
opposite the direction of displacement.
-50V
-25V
e) How much work is done by the electric field in moving a +3 µC point
charge from B to D? Explain. 25V(3 µC)=75x10-6 J
f) Find a location (A-G) that is at a higher electrical potential than at D.
F or G
g) Find a location (A-G) that is at the same electrical potential as at D.
C
h) Find a location (A-G) where a positive test charge would have a higher
electrical potential energy than at D.
F or G
i) Describe this region using the geographical analogy (topographical maps).
What will this region “look” like for a positive charge?
Area is looking down into long and narrow pit or valley that is all below sea
level.
Phy 122
spr 09