Question

A plane wave is incident normally on a perfect conductor as shown in figure, Here $E_x^i,H_y^i$ and $\overrightarrow{p^i}$ are electric field, magnetic field and poynting vector, respectively, for the incident wave. The reflected wave should have

Answer 1

Ans : (a & c)

Reflection coefficient for electric fields

${\Gamma }_E=\frac{\sqrt{\frac{j\omega \mu }{\sigma }}-120\pi }{\sqrt{\frac{j\omega \mu }{\sigma }}+120\pi }=-1forconductors$

As $\eta =\sqrt{\frac{j\omega \mu }{\sigma }}\simeq 0$ with $\sigma$ being large


when E reflection completely out of phase, H reflects in phase

$E_x^r=-E_x^i$

$H_x^r=-H_x^i$

So, $\overrightarrow{P^r}=-\overrightarrow{P^i}$