The ability of an electromagnetic wave to pass through holes or obstacles primarily depends on its wavelength, rather than its amplitude. This phenomenon is known as diffraction.
Diffraction occurs when a wave encounters an obstacle or a slit that is comparable in size to its wavelength. When a wave passes through a small opening or encounters an obstacle with dimensions similar to its wavelength, it tends to spread out and bend around the edges of the obstacle. This bending and spreading out of the wave is characteristic of diffraction.
The extent of diffraction depends on the wavelength of the wave. When the wavelength is larger relative to the size of the opening or obstacle, the wave will diffract more. Conversely, when the wavelength is smaller relative to the size of the opening or obstacle, the wave will diffract less.
Amplitude, on the other hand, determines the intensity or strength of the wave. It represents the energy carried by the wave but does not significantly affect the wave's ability to pass through small openings or obstacles.
To summarize, the wavelength of an electromagnetic wave determines its ability to diffract and pass through holes or obstacles, while the amplitude of the wave affects its intensity or strength.