Correct Answer : Option (D) : No real power flow occurs in the ‘z’ direction
Explanation : The superposition of the two plane waves in Z direction is such that complete cancellation occurs at y=0 and y=d, to satisfy the boundary conditions that Ez=0 at these planes. As f decrease to fc, β approaches 0 so that θ approaches 90â°. The two plane waves are then bouncing up and down, with no motion in +z direction, and no power flow occurs in the z direction.
