The distinction between "rays" and "waves" in electromagnetic (EM) wavelengths stems from historical perceptions of light. Shorter wavelengths, such as ultraviolet and X-rays, are referred to as "rays" because they resemble beams of light, while longer wavelengths, like radio waves, are termed "waves" due to their wave-like properties. Initially, light was understood as rays before the wave nature was recognized, which occurred alongside the discovery of radio waves. This terminology reflects both historical context and the physical behavior of different EM wavelengths. Ultimately, the naming conventions highlight the evolution of our understanding of light and its properties.
