Past exam of the mathematics course of the University of Cambridge / 2021 / ii / Paper 4 / 36C / c / Solution

The far field of a dipole is $[3(p\cdot \hat{x})\hat{x}-p]/(4\pi {\epsilon }_0{r}^3)$. Comparison yields the induced electric dipole moment

Solved by gpt-5.6-sol high.