The Physics Factbook™
Edited by Glenn Elert -- Written by his students
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|Faughn, Jerry S. & Raymond A. Serway. College Physics, 6th ed. Canada: Thomson, Brooks/Cole, 2003: 675.||"The eye's sensitivity is a function of wavelength and is greatest at a wavelength of about 5.6 × 10-7 m (yellow-green)."||560 nm|
|Photopic Vision. Wikipedia, 2007||"The maximum efficacy is 683 lumens/W at a wavelength of 555 nm (green)."||555 nm|
|Bradley, Arthur, Larry Thibos, & Xiaoxiao Zheng. Achromatizing the Human Eye. Indiana University, 1989.||"Most of the light in a broad spectrum white is concentrated around the peak of the photopic luminosity function (555nm), and if a wavelength near 555nm is in focus, most of the light will be less than 0.25 diopters out of focus."||555 nm|
|Hattori, Tadashi, Takasi Taguchi, & Yashiki Ueno. Antiglare Mirror for an Automobile. US Patent, 29 Sept. 1987.||"In this spectral reflection, the maximum reflection exists in a blue zone, which means that the mirror gives off blue reflected light when no voltage is applied to the electrodes 2 and 7, and the visual reflectivity is approximately 44% since the maximum human visual sensitivity is approximately 550 nm."||550 nm|
|McGrath, Kimberley A. World of Biology. USA: The Gale Group, 1999: 707.||"Wavelengths of approximately 565 nm (yellow light) are perceived by both green and red cones, therefore yellow appears as a very bright color."||565 nm|
|Cone Cell. Wikipedia, 2007.||"The first responds most to light that has a long wavelength, which is yellowish-green. It is abbreviated L. The second type responds most to light of medium-wavelength, which is bluish-green, it is abbreviated M. The third type responds most to short-wavelength light, which is blue-violetish, abbreviated S. The three types have have peak wavelengths of 564 nm, 534 nm, and 420 nm respectively."||L–564 nm
Eyes are organs of vision that detect light. Some eyes just detect whether the surroundings are light or dark while more complex eyes can distinguish shapes and colors. In humans and most other vertebrates, the eye allows light to enter and projects it onto the retina at the rear of the eye. The retina consists of photoreceptor cells called rods and cones. The cones are at the center of the retina, and the rods are at the outer edge of the retina. There are about seven million cones and a hundred million rods. At the retina, the light is detected and converted to electrical signals. These signals are then transferred to the brain through the optic nerve. The brain converts these signals into our view of the world.
The human eye detects visible light, part of the electromagnetic spectrum. Light is produced by rearranging electrons in atoms and molecules. The wavelengths of visible light range from about 400 nm to about 700 nm. Photopic vision is the scientific term for human vision under normal lighting conditions during the day. This allows for color perception. The cones in the retina help us to see the colors. There are three types of cones in the human eye. Each type of cone absorbs light waves of specific frequencies: long wavelengths (L), medium wavelengths (M), and short wavelengths (S). The peak wavelength of L is 564 nm, yellowish-green. The peak of M is 534 nm, bluish-green. The peak of S is 420 nm, bluish-violet.
Colors are perceived when the cones are stimulated. The color perceived depends on how much each type of cone is stimulated. Yellow is perceived when the yellow-green receptor is stimulated slightly more than the blue-green receptor. The eye is most sensitive to green light (555 nm) because green stimulates two of the three kinds of cones, L and M, almost equally.
Susan Zhao -- 2007
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