Question

The distance of the field point on the axis of a small dipole is doubled. By what factor will the electric field, due to the dipole change?

Answer 1

For a small dipole, \(E_{a\text xis}=\cfrac{1}{4\pi\varepsilon_0}\cfrac{2p}{r^3}\propto\cfrac1{r^3}\) 

When the distance r is doubled, the electric field strength becomes 1/8 times the original field.