Question

from
69
V
VA = 16
Varmte 3 +
V
① Derive an expression for the potencial at a point de
to an electric dipole
?
​

Answer 1

Answer:

Consider an electric dipole AB in which point charges +q and -q are separated by a distance 2l. Let P be a point on it's axis seperated by a distance r from the dipole's center O.

Electric dipole moment, p = q (2l)

Electric potential (V

A

) due to +q charge

V

A

=

4πϵ

0

1

r−l

q

Electric potential (V

B

) due to +q charge

V

B

=

4πϵ

0

1

r+l

−q

Therefore, total electric potential at P due to dipole will be

V=

4πϵ

0

q

[d

r−l

1

−

r+l

1

]

=

4πϵ

0

q

r

2

−l

2

2l

=

4πϵ

0

p

r

2

−l

2

1

Now, l<<r (short dipole)

V=

4πϵ

0

p

r

2

1

(for axial position)