High School Physics

# Electric Field of an electric dipole on axial and equatorial points – formulas

In this page, you will get the formulas required to calculate the electric field intensity due to an electric dipole on axial and equatorial points. The vector forms of these formulas are also provided.

An axial point is also known as the end-on position. The equatorial point is on the perpendicular bisector of the dipole, and this point is also known as the broad-side-on position.

## Electric field due to an electric dipole on an axial point – Formula

Electric field due to an electric dipole on the axial point:

Eaxial = (1/4πε0) 2p/r3

The direction of this electric field is along the direction of the dipole moment p (this means from the negative charge to the positive charge of the dipole)

## Electric field due to an electric dipole on an equatorial point – Formula

Electric field due to an electric dipole on the equatorial point:

Eequatorial = (1/4πε0) p/r3

The direction of this electric field is antiparallel to the dipole moment p or in other words, this field is along the opposite direction of the dipole moment p.

### explanation of the parameters in the dipole electric field formulas

In the above equations, p = q 2l = dipole moment.

Dipole moment p is a vector whose direction is from the negative charge of the dipole to the positive charge of that dipole.

q is the amount of charge on each end of the dipole (one end with +q and the other end has -q).

2l is the distance between the positive and the negative charge of the electric dipole.

r is the distance between the point where the electric field is being calculated and the midpoint of the dipole.