For a prism of prism angle $\theta=60^{\circ}$, the refractive indices of the left half and the right half are, respectively, and ( $n_2 \geq n_1$ ) as shown in the figure. The angle of incidence $i$ is chosen such that the incident light rays will have minimum deviation if $=n=1.5$. For the case of unequal refractive indices, $n_1=n$ and $n_2=n+\Delta n$ (where $\Delta n \ll n$ ), the angle of emergence $e=i+\Delta e$. Which of the following statement(s) is (are) correct ?