GATE Electronics and Communications (EC) 2021 Solved Paper

Consider a rectangular coordinate system (x, y, z) with unit vectors a_x, a_y, and a_z. A plane wave traveling in the region z ≥ 0 with electric field vector E = 10 cos (2 × 10⁸ t + βz) a_y is incident normally on the plane at z = 0, where β is the phase constant. The region z ≥ 0 is in free space and the region z < 0 is filled with a lossless medium (permittivity ε = ε₀, permeability μ = 4μ₀, where ε₀ = 8.85 × 10^-12 F/m  and μ₀ = 4π × 10^-7 H/m). The value of the reflection coefficient is