3. A plane wave in free space with an electric field intensity of 3 cos (cot-z)ŷ V/m is incident on a large block of material with a dielectric constant of 12, a relative permeability of 3, and a conductivity of 0, which occupies z≥0. Determine the average power that passes through a circle of radius 90 cm in the plane z = 5 m.