{\large \left. \begin{array}{l}\left. \begin{array}{l}\sigma \,=\,{{\varepsilon }_{0}}\cdot E\\\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,E\,=\,\frac{U}{d}\end{array} \right\}\,\Rightarrow \,\sigma \,=\,{{\varepsilon }_{0}}\cdot \frac{U}{d}\\\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,Q\,=\,\sigma \,\cdot \,A\end{array} \right\}\,\Rightarrow \,Q\,=\,\frac{{{\varepsilon }_{0}}\cdot \,U\,\cdot \,A}{d} }