As a result of reflection from a plane conducting wall, electromagnetic waves acquire an apparent velocity greater than the velocity of light in space.
This is called the
A. velocity of propagation.
B. normal velocity.
C. group velocity.
D. phase velocity.
Answer: D
Share your understanding of this question with the correct explanation.
As a result of reflection from a plane conducting wall, electromagnetic waves acquire an apparent velocity greater than the velocity of light in space. This is called the phase velocity. Therefore, the correct answer is D: “phase velocity.”
Here’s a further explanation:
The phase velocity is a concept used to describe the apparent velocity at which the phase of a wave propagates through a medium. It represents the speed at which the wavefronts or phase of the wave propagate.
When an electromagnetic wave encounters a plane conducting wall, such as a metallic surface, it undergoes reflection. Due to the interaction between the wave and the conducting wall, the phase velocity of the reflected wave can be greater than the velocity of light in space.
This can be understood by considering the wave’s behavior near the boundary of the conducting wall. The interaction with the conducting wall can lead to a delay in the wave’s phase, resulting in a phase velocity that appears greater than the speed of light.
It’s important to note that the phase velocity does not represent the actual propagation speed of information or energy. In fact, the phase velocity can exceed the speed of light, but the energy and information associated with the wave still propagate at the speed of light in the medium.
Therefore, in the context of reflection from a conducting wall, the apparent velocity acquired by electromagnetic waves is referred to as the phase velocity (option D).