The electric field in an electromagnetic wave is given by $\mathrm{E}=56.5 \sin \omega(\mathrm{t}-\mathrm{x} / \mathrm{c}) \mathrm{NC}^{-1}$. Find the intensity of the wave if it is propagating along $x$-axis in the free space. (Given $\varepsilon_0=8.85 \times 10^{-12} \mathrm{C}^2 \mathrm{~N}^{-1} \mathrm{~m}^{-2}$ )