Rationalised 2023-24
Electric Charges
and Fields
39
12 Field of an electric dipole in its equatorial plane (i e , the plane
perpendicular to its axis and passing through its centre) at a distance
r from the centre:
2
2 3/2
1
4
(
)
o
a
r
ε
−
=
π
+
p
E
3 ,
4
o
for r
a
−εr
≅
>>
π
p
Dipole electric field on the axis at a distance r from the centre:
2
2 2
0
2
4
(
)
r
r
a
ε
=
π
p−
E
3
0
42
for
r
a
εr
≅
>>
π
p
The 1/r3 dependence of dipole electric fields should be noted in contrast
to the 1/r 2 dependence of electric field due to a point charge