An EM wave from air enters a medium. The electric fields are E_1= E_01 x cos [2 π ν(z/c-t)] in air and E_2= E_02 x cos [ k (2 z- ct )] in medium,…

An EM wave from air enters a medium. The electric fields are $\displaystyle \overrightarrow{\mathrm{E}}_1=\mathrm{E}_{01} \hat{x} \cos \left[2 \pi \nu\left(\frac{z}{c}-t\right)\right]$ in air and $\displaystyle \overrightarrow{\mathrm{E}}_2=\mathrm{E}_{02} \hat{x} \cos [\mathrm{k}(2 z-\mathrm{ct})]$ in medium, where the wave number k and frequency $\displaystyle \nu$ refer to their values in air. The medium is non-magnetic. If $\displaystyle \epsilon_{\mathrm{r}_1}$ and $\displaystyle \epsilon_{\mathrm{r}_2}$ refer to relative permittivities of air and medium respectively, which of the following options is correct ?