Electric Field from a Point Charge

Consider the electric force equations

F = kq1q2/r**2

and

F = e q2

we can see that

e = kq1/r**2

compare with the equation for g from a point mass

g=Gm/r**2

Note:
e
compares with
g
k
compares with
G
q
compares with
m
Symbol
Description
Units
e
the electric field strength
N/C
k

The Coulomb constant

8.99 x 10**9
Nm**2C**-2
q
Electric charge
C
r
distance from centre of charge to the point that the E strength is being determined
m

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