Physics - EM Waves Question with Solution | TestHub

Given, $E=56.5\sin \omega \left(\frac{t-x}{c}\right) \mathrm{N} {\mathrm{C}}^{-1}$

Comparing it with the general equation of electromagnetic wave, 

$E=E_0\sin \left(\omega t-kx\right)$

We have, $E_0=56.5 \mathrm{N} {\mathrm{C}}^{-1}$

So, the intensity will be  $I=\frac{1}{2}{\epsilon }_0{E}_0^{2}c$

$=\frac{1}{2}\times 8.85\times {10}^{-12}\times {\left(56.5\right)}^2\times 3\times {10}^8$

$=4.24 \mathrm{W} {\mathrm{m}}^{-2}$