____________________ is the color of the visible spectrum with the longest wavelength.
Colors containing only one wavelength are also called pure colors or spectral colors. Visible wavelengths pass through the  optical window , the region of the electromagnetic spectrum that allows wavelengths to pass largely unattenuated through the Earth's atmosphere. An example of this phenomenon is that clean air scatters blue light more than red wavelengths, and so the midday sky appears blue. Light, no matter how complex its composition of wavelengths, is reduced to three color components by the eye. For each location in the visual field, the three types of cones yield three signals based on the extent to which each is stimulated. It includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range (that is, what we commonly refer to simply as light). White light is dispersed by a prism into the colors of the visible spectrum. The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 700 nm. In terms of frequency, this corresponds to a band in the vicinity of 430–770 THz. Color, or colour (see spelling differences) is the visual perceptual property corresponding in humans to the categories called red, blue, yellow, etc. Color derives from the spectrum of light (distribution of light power versus wavelength) interacting in the eye with the spectral sensitivities of the light receptors. The familiar colors of the rainbow in the spectrum – named using the Latin word for appearance or apparition by Isaac Newton in 1671 – include all those colors that can be produced by visible light of a single wavelength only, the pure spectral or monochromatic colors. When we consider light as an electromagnetic wave, a color's spectral signature may be identified by noting its wavelength. We sense the waves as color, violet being the shortest wavelength and red the longest. Visible light is the range of wavelengths within the electromagnetic spectrum that the eye responds to. Although radiation of longer or shorter wavelengths are present, the human eye is not capable of responding to it. Figure 2. It's not possible to list them all, since there are an infinite  number of them.    -- The color with the longest visible wavelength is the last one  you see   at … the red end of the rainbow.    -- The color with the shortest visible wavelength is the last one  you see   at the violet end of the rainbow. You could memorize the seven spectrum colors in order with a word called [roygbiv] or Roy G. Biv, as most learn it. The colors of the rainbow are in the order from longest wavelength to shortest, with red having the longest wavelength and violet having the shortest. r= red. The color red is the longest wavelength in the visible light spectrum because the less energy a wave carries the longer the wavelength and red carries the least energy of all … the colors in the visible spectrum.
Red