I suppose you mean how far it can go. There is no limit how far it can go, but any light will get weaker as it gets spread over a larger space. That doesn't depend on the color of the light.
Red light has wavelengths in the range 622-780 nm.
Red object is one that absorb other range of spectrum but Red light.
The type of electromagnetic wave the borders visible light at the red end of its range is the Infrared light wave.
750 nanometers corresponds to the wavelength range of red light.
to make red you need to put to together yellow and dark pink.
Blue and Red
Blue and Red -Mastering Biology 4th edition
The range of wavelengths that are visible is approximately 400 nm to 600 nm. A nm is a nanometer, one billionth of a meter. Blue light is in the 400 nm range, yellow light in the 500 nm range and red light in the 600 nm range.
That depends on whether it's still in the visible light range that human eyes can detect. If it's beyond red it will be infrared, a light wave with wavelength/frequency that we cannot detect. The frequency range of red light is between 484 THz to 384 THz. The wavelength of visible red light is between 620 nm to 750 nm.
The waves with a length of 0.4-0.7 micrometers are considered to be in the visible spectrum, specifically in the range of red light to violet light. This range corresponds to wavelengths commonly associated with colors we can see with our eyes.
It means the wearer is in range. If the wearer is out of range, the red light comes on (possibly intermittently) and the yellow light goes off.
The wavelengths of light absorbed by pigments in the granum are mainly in the blue and red range of the spectrum. This is because chlorophyll, the main pigment in photosynthesis, primarily absorbs light in the blue and red wavelengths for energy conversion.