MCQ
An EM wave from air enters a medium. The electric fields are $\overrightarrow {{E_1}} = {E_{01}}\hat x\;cos\left[ {2\pi v\left( {\frac{z}{c} - t} \right)} \right]$ in air and $\overrightarrow {{E_2}} = {E_{02}}\hat x\;cos\left[ {k\left( {2z - ct} \right)} \right]$ in medium, where the wave number $k$ and frequency $v$ refer to their values in air. The medium is nonmagnetic. If $\varepsilon {_{{r_1}}}$ and $\varepsilon {_{{r_2}}}$ refer to relative permittivities of air and medium respectively, which of the following options is correct?
- A$\frac{{{_{{\in r_1}}}}}{{{_{{\in r_2}}}}} = 2$
- ✓$\frac{{{_{{\in r_1}}}}}{{{_{{\in r_2}}}}} = \frac{1}{4}$
- C$\frac{{{_{{\in r_1}}}}}{{{_{{\in r_2}}}}} = \frac{1}{2}$
- D$\frac{{{_{{\in r_1}}}}}{{{_{{\in r_2}}}}} = 4$
