The phenomenon you are describing is known as the interaction of light with a metal, specifically in the context of the skin effect and the reflection of light from a metal surface. When light interacts with a metal, the incident electromagnetic (EM) waves induce the oscillation of free electrons in the metal. These oscillating electrons then emit their own EM waves, which can interfere with the incident waves.
However, it's important to note that the interference between the incident and reflected waves does not result in complete cancellation outside the metal. There are a few reasons for this:
The reflected waves are not completely out of phase with the incident waves: While the oscillating electrons produce waves that are out of phase with the incident waves, the degree of phase shift depends on various factors such as the metal's properties, the angle of incidence, and the frequency of light. In general, the reflected waves do interfere with the incident waves, leading to a change in the resulting wave amplitudes and directions. However, complete cancellation is not typically observed.
The metal's reflectivity: Metals are known for their high reflectivity, especially for visible light and other lower-frequency electromagnetic waves. This means that a significant portion of the incident light is reflected rather than absorbed by the metal. The reflected light retains its own intensity and carries its own energy, contributing to the overall reflected wave.
Multiple reflections and scattering: When light interacts with a metal surface, multiple reflections and scattering events occur. The incident light may undergo multiple interactions with the oscillating electrons in the metal, resulting in a complex interplay of waves. These multiple interactions can lead to constructive or destructive interference effects, but again, complete cancellation is not the dominant outcome.
In summary, while the oscillation of free electrons in a metal can generate waves that interfere with incident light, resulting in changes to the amplitude and direction of the reflected waves, complete cancellation of the reflected waves outside the metal is not typically observed. The reflectivity of metals, multiple reflections, and scattering events all contribute to the final wave pattern.