Which electromagnetic radiation has frequencies lower than the red color in visible light?

Electromagnetic radiation with frequencies lower than red light in the visible spectrum falls within the infrared range. Infrared radiation has longer wavelengths than visible light, specifically longer than the wavelengths associated with red light.

Red light has a frequency of approximately 430–480 terahertz, and the next range of lower frequencies corresponds to infrared radiation, which spans from about 300 gigahertz to 430 terahertz.

This position in the electromagnetic spectrum is significant; infrared radiation is commonly associated with heat, as objects emit infrared radiation when they are warm. This fundamental understanding of the electromagnetic spectrum is crucial, especially regarding applications in communication, thermal imaging, and remote sensing technologies.