The electric field at a point on the equatorial plane at a distance r from the centre of a dipole having dipole moment $\overrightarrow{\mathit{p}}$ is given by ($r>>$ separation of two charges forming the dipole, ${ϵ}_0$- permittivity of free space)

• A

  $\overrightarrow{E}=\frac{\overrightarrow{P}}{4\pi {ϵ}_0{r}^3}$
• B

  $\overrightarrow{\mathit{E}}=\frac{2\overrightarrow{P}}{4\pi {ϵ}_0{r}^3}$
• C

  $\overrightarrow{E}=-\frac{\overrightarrow{P}}{4\pi {ϵ}_0{r}^2}$
• Correct answer
  D

  $\overrightarrow{\mathit{E}}=-\frac{\overrightarrow{P}}{4\pi {ϵ}_0{r}^3}$

Hence, the correct answer is option: 'D'.