The ability of an electromagnetic wave to pass through holes or obstacles primarily depends on its wavelength, not its amplitude. This phenomenon is known as diffraction.
Diffraction occurs when waves encounter an obstacle or a slit that is comparable in size to their wavelength. When this happens, the waves bend or spread out around the edges of the obstacle or slit, leading to the phenomena of diffraction patterns and interference.
The extent of diffraction depends on the ratio of the size of the obstacle or slit to the wavelength of the wave. When the size of the obstacle or slit is similar to or smaller than the wavelength of the wave, diffraction becomes significant.
The wavelength of an electromagnetic wave determines the scale of its oscillations in space. If the wavelength is comparable to or larger than the size of the hole or obstacle, the wave will tend to diffract and spread out, allowing it to pass through the hole or bend around the obstacle.
In contrast, the amplitude of an electromagnetic wave relates to its intensity or brightness. It represents the magnitude or strength of the electric and magnetic fields associated with the wave. While the amplitude affects the intensity of the wave, it does not directly impact the diffraction characteristics of the wave.