An EM wave from air enters a medium. The electric fields are E → 1 = E 01 x ^ cos ⁡ 2 π v z c - t in air and E → 2 = E 02 x ^ cos ⁡ k 2 z - c t in medium, where the wave number k and frequency v refer to their values in the air. The medium is non-magnetic. If ϵ r 1 and ϵ r 2 refer to relative permittivities of air and medium respectively, which of the following options, is cor