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Physics
Physics
Problem
Which expression represents the magnitude of the electric field at a distance
r
r
r
from an isolated point charge
Q
Q
Q
in vacuum? a)
k
Q
4
r
2
\displaystyle \frac{kQ}{4r^{2}}
4
r
2
k
Q
b)
k
Q
r
2
\displaystyle k\frac{Q}{r^{2}}
k
r
2
Q
c)
4
π
k
Q
r
2
\displaystyle 4\pi k\frac{Q}{r^{2}}
4
π
k
r
2
Q
d)
2
k
Q
r
2
\displaystyle \frac{2kQ}{r^{2}}
r
2
2
k
Q
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