Question

The distance of the field point on the equatorial plane of a small electric dipole is halved. By what factor does the electric field due to the dipole change?

Answer 1

For a small electric dipole

E_equi = \(\frac{1}{4\piɛ_o} \frac{q}{r^3}\)

or E_equi ∝ \(\frac{1}{r^3}\)

So when r is made \(\frac{r}{2}\), the electric field intensity will increase 2³ = 8 times the original field.