c
\({\text{W}} = {{\text{U}}_{\text{f}}} - {{\text{U}}_{\text{i}}} = \frac{{{{\text{Q}}^{\text{2}}}}}{{2C'}}{\text{ - }}\frac{{{{\text{Q}}^{\text{2}}}}}{{2C}}\)(જેમ \(Q\) અચળ છે)

\({\text{C}} = \frac{{{\varepsilon _{\text{0}}}A}}{d}\,\,\,\, \Rightarrow \,\,C' = \frac{{{\varepsilon _0}A}}{{2d}} = \frac{C}{2}\)

\({\text{W}} = \frac{{{{\text{Q}}^{\text{2}}}}}{C} - \frac{{{Q^2}}}{{2C}} = \frac{{{Q^2}}}{{2C}}\) પરંતુ  \({\text{Q}} = {\text{CV}}\,\,\, \Rightarrow \,\,\,\,{\text{W}} = \frac{{{\text{C}}{{\text{V}}^{\text{2}}}}}{2} = \frac{{{\varepsilon _0}A{V^2}}}{{2d}}\)