- Electric field due to an electric dipole at a point on its axial line
- Electric field due to an electric dipole at a point on the

equatorial line. - Electric dipole in a uniform electric field

**Electric field due to an electric dipole at a point on its axial line**

AB = electric dipole

-q, +q = two point charges

2d = small distance separating the two opposite point charges

P = point along the axial line of the dipole at a distance r from the midpoint O of the electric dipole

E1 and E2 = electric fields acting on the point P in opposite directions

Because, electric dipolemoment, p = q x 2d

E acts in the direction of diplolemoment.

**Electric field due to an electric dipole at a point on the equatorial line**

- The magnitudes of E1 and E2 are equal.
- E1 and E2 are resoved into their horizontal and vertical components.
- E1 sin θ and E2 sin θ are equal and opposite, therefore

they cancel each other. - The horizontal components E1 cos θ and E2 cos θ will get added

along PR.

**Electric dipole in a uniforms electric field**

AB = electric dipole

p = dipole moment

θ = angle of dipole kept in the electric field, E

- The charge +q experiences a force qE in the direction of the field.
- The charge –q experiences an equal force in the opposite direction.
- The net force on the dipole is zero.
- The two and unlike parallel forces are not passing through the same point.
- It results in a torque (a twisting force) on the dipole.
- It tends to set the dipole in the direction of the electric field.