c
સરેરાશ ઉર્જા ઘનતા \({{\text{u}}_{\text{E}}}\, = \,\,\frac{1}{2}{\varepsilon _o}{E^2}\,\)

\( = \,\,\frac{1}{2}{\varepsilon _o}{\left( {\frac{{{E_o}}}{{\sqrt 2 }}} \right)^2}\, = \,\,\frac{1}{4}{\varepsilon _o}E_o^2\,\, = \,\,\frac{1}{4}\,\, \times \,\,8.85\,\, \times \,\,{10^{ - 12}}\, \times \,\,{(1)^2}\, = \,\,2.2\,\, \times \,\,{10^{ - 12}}\,J/{m^2}\)