Topic: Electromagnetics
The change in phase of an electromagnetic wave normally incident on a perfect conducting wall is?
- A. $90^{\circ}$
- B. $180^{\circ}$
- C. $0^{\circ}$
- D. $270^{\circ}$
Answer: B. $180^{\circ}$
Explanation: The reflection coefficient for the electric field of an electromagnetic wave normally incident on a perfect conducting wall is -1. This negative sign indicates a phase change or phase shift of $180^{\circ}$ upon reflection.