Demonstrate that the potential of the field generated by a dipole with the electric moment \(\mathbf{p}\) (Fig. 3.4) may be represented as \(\varphi=\mathrm{pr} / 4 \pi \varepsilon_{0} r^{3},\) where \(\mathbf{r}\) is the radius vector. Using this expression, find the magnitude of the electric field strength vector as a function of and \(\theta\)