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Physics
Physics
Problem
A
+
4.0
μ
C
+4.0\,\mu\text{C}
+
4.0
μ
C
point charge and a
−
4.0
μ
C
-4.0\,\mu\text{C}
−
4.0
μ
C
point charge are brought from infinity to a separation of
0.10
m
0.10\,\text{m}
0.10
m
. What is the change in electric potential energy
Δ
U
\Delta U
Δ
U
of the two–charge system? (Use
k
=
8.99
×
10
9
N
m
2
/
C
2
k=8.99\times10^{9}\,\text{N\,m}^2\!\,/\!\,\text{C}^2
k
=
8.99
×
1
0
9
N
m
2
/
C
2
.) a)
+
1.44
J
+1.44\,\text{J}
+
1.44
J
b)
−
1.44
J
-1.44\,\text{J}
−
1.44
J
c)
−
0.72
J
-0.72\,\text{J}
−
0.72
J
d)
−
14.4
J
-14.4\,\text{J}
−
14.4
J
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