(1) How many LED’s are in the large video screen at the Arizona Football Stadium?<\/p>\n
HINT: See our notes for Lecture 5.
\n\u25aa We defined “pixel pitch” as the spacing between each pixel.
\n\u25aa For this problem, assume 3 LED’s per pixel (1 Red, 1 Green, and 1 Blue)
\n\u25aa There are 25.4mm per inch<\/p>\n
(2) Consider a 100W incandescent tungsten light bulb. Assume that the temperature of the filament is 2500\u00b0C.
\nWhat is the wavelength where the light output from this bulb peaks (is maximum)?<\/p>\n
HINT: Use the equation that we talked about in class: \u03bb\u00b7T = 3000 (\u03bcm\u00b7K)
\nQuote your answer in nanometers.<\/p>\n
(3) If you want to shift this peak output to a longer wavelength, what must happen to the temperature? Explain.<\/p>\n
(4) In class, we saw the demo where I aimed red, green, and blue laser beams on the wall. For this problem, assume
\nthat each laser emitted 5mW of optical power. Calculate the number of lumens in each beam.<\/p>\n
HINT: Use the curve showing the response of the human eye to various wavelengths, on page L5-8.<\/p>\n
\u03bb(blue) = 405 nm ; \u03bb(green) = 532 nm ; \u03bb(red) = 650 nm<\/p>\n