The average energy density of electromagnetic wave given by $\mathrm{E}=(50\mathrm{N}/\mathrm{C})\sin (\mathrm{\omega t}-\mathrm{kx})$ will be nearly

• A

  ${10}^{-8}\mathrm{J}/{\mathrm{m}}^3$

• B

  ${10}^{-7}\mathrm{J}/{\mathrm{m}}^3$

• C

  ${10}^{-6}\mathrm{J}/{\mathrm{m}}^3$

• D

  ${10}^{-5}\mathrm{J}/{\mathrm{m}}^3$