What is Red? Physics and optics Red is the colour at the longer-wavelengths end of the spectrum of visible light next to orange, at the opposite end from violet. Red colour has a predominant light wavelength of roughly 620–740 nanometers. Light with a longer wavelength than red but shorter than terahertz radiation and microwave is called…

Source: Wikipedia Blue and links therefrom What is Blue? Physics and Optics Blue is the colour between violet and green on the optical spectrum of visible light. Human eyes perceive blue when observing light with a wavelength between 450 and 495 nanometres. Blues with a higher frequency and thus a shorter wavelength gradually look more violet, while…

Sources: Wikipedia  Yellow What is Yellow? Physics and Optics Yellow is the colour between green and orange in the spectrum of visible light. It is the brightest and lightest of all colours. As the colour of sunlight, it is commonly associated with warmth, combined with red with heat and energy. A room painted yellow feels warmer than a…