JEE PHYSICS MCQ: ELECTROMAGNETIC WAVES

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