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