
$\mathrm{E}_{2} \mathrm{A}-\mathrm{E}_{1} \mathrm{A}=\frac{\mathrm{q}_{\mathrm{in}}}{\varepsilon_{0}}$
$\mathrm{JA}\left(\frac{1}{\sigma_{2}}-\frac{1}{\sigma_{1}}\right)=\frac{\mathrm{q}_{\mathrm{in}}}{\varepsilon_{0}}$
${\varepsilon _0}I\left( {\frac{1}{{{\sigma _2}}} - \frac{1}{{{\sigma _1}}}} \right) = {q_{{\rm{in}}}}$




