Red.
Red has the longest wavelength in the visible spectrum of light.
Red light has the longest wavelength in the visible light spectrum.
That's the last color you can see on the red end of the spectrum.
Red light has the longest wavelength in the visible spectrum.
Red light has the longest wavelength in the visible spectrum.
Radio waves
voilet
Radio waves are the electromagnetic waves with longest wavelength.
The color red has the largest wavelength. The color violet, on the other hand, has the shortest wavelength.
Radio waves have the longest wavelength among the electromagnetic spectrum, ranging from several meters to kilometers in length.
length
There is no longest wave-length for light. It can be infinitely long (just as light waves could be infinitely short). The longest visible light that humans can see is about 750 nanometers long, which is 0.00075 of a millimeter. This color would be a shade of red. Some other animals and insects can see slightly longer wavelengths, and many can not even see what we can.