RGB colors

With red, green, and blue light, new colors can emerge by mixing the light. RGB differs from colors mixed on paper, which is instead called CMYK, cyan, magenta, yellow, and black. White light contains all colors, therefore colors are clearly visible in white natural light. When I illuminate a green apple with white natural light, the apple appears green. If instead, I only use red light, no light is reflected from the green apple, which then appears black. The light is absorbed and appears black. Interested in what color is and how the eye reads more in Physics 9 in Apple Books.