Why can radio-frequency waves not be seen?

Radio-frequency waves cannot be seen because they fall below the sensitivity range of the human eye. The human visual spectrum is limited to a specific range of wavelengths, typically from about 400 nanometers (violet) to about 700 nanometers (red). Radio-frequency waves, which include those used for communication, operate at much longer wavelengths (ranging from millimeters to kilometers), significantly beyond the visible spectrum.

Consequently, while we can interact with radio waves through technology such as radios and antennas, the physical limitations of human vision prevent us from detecting these frequencies naturally. This understanding highlights the important principle that the electromagnetic spectrum encompasses a wide variety of frequencies and wavelengths, only a small portion of which we can see.