Example:%20Potential%20Difference%20of%20Point%20Charges

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Example Potential Difference of Point
Charges Consider a point charge q. What is the
potential difference between point x1 and point
x2?
q
x2
x1
DV depends on starting, ending point
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Potential Difference and Potential of Point
Charge Can check all cases q positive or
negative r1 gt r2 or r2 gtr1 1?2 or 2?1
q
r1
r2
HAVE to talk about potential DIFFERENCE One
exception Potential of point charge WITH
RESPECT TO INFINITY
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ConcepTest 9 Consider the positive point
charge shown in the figure. What is the
potential difference going from point A at
distance a to point B at distance b?
B
A

4
d
ConcepTest 10 Consider four identical point
charges q arranged at the corners of a square of
side length d as shown in the figure. What is
the electric potential at the center of the
square (relative to infinity)?
-
-
d
-
-
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Example Spherical Conductor, Field, Potential
Consider a thick neutral spherical conducting
shell with inner radius a and outer radius b. A
positive point charge Q is at the center of the
shell, as shown. 1) Write down the electric
field in the regions i) r lt a ii) a lt r
ltb iii) r gt b 2) Set the potential at r 8 to
zero. Determine the electric potential in the
regions i) r gt b ii) a lt r ltb
iii) r lt a
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Current, Potential Difference, and Electric
Field in Conductors (?)
Current motion of charge (charge flow).
Amount of charge that passes a point (or through
a cross sectional area) in some amount of time.
How can there be electric field in conductor? If
electric field in conductor, why dont charges
accelerate?