The color to which the human eye is most sensitive is a yellowish green with a w
ID: 2154294 • Letter: T
Question
The color to which the human eye is most sensitive is a yellowish green with a wavelength of approximately 550 nm. (For this "scientific" reason there was a brief vogue in the 1980s for making fire trucks this color, a fad that faltered when departments found that firefighters took little pride in non-red fire trucks and consequently maintained them poorly. In fact, the photographer of the accompanying picture was told that the truck will be painted red "within a month ? red is traditional".) (a) What is the frequency of waves of this color? (b) How many wavelengths of this yellowish green light are there in the thickness of a human hair that is 110 ?m in diameter? (c) How many wavelengths of the light are there in the width of a pencil, 6.00 mm?Explanation / Answer
F = c/L, where L = wavelenght c= velocity of light 550 nm = 550*10^-9 m c = 3*10^8 m 3*10^8/550*10^-9 = 4.45*10^14 Hz 110 µm = 110*10^-6 m, n = 110*10^-6 / 550*10^-9 = 200 wavelengths 6 mm = 6*10^-3 m n = 6*10^-3 / 550*10^-9 = 10,909 wavelengths