The electric field in an electromagnetic wave is given as \( \vec{E} = 20\sin \omega \left( t - \dfrac{x}{c} \right) \vec{j} \; \text{N C}^{-1} \) where \( \omega \) and \( c \) are angular frequency and velocity of electromagnetic wave respectively. The energy contained in a volume of \( 5\times10^{-4} \; \text{m}^{3} \) will be:
(Given \( \varepsilon_{0}=8.85\times10^{-12} \; \text{C}^{2}/\text{N m}^{2} \))
