MATH 2270 Lecture Notes - Luminous Intensity, Junit, Integrating Factor
21 Dec 2013
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Document Summary
Diminishing visibility with distance can be quanti ed by a constant b, called the extinction coe cient, that satis es the equation. The dependent variable i represents light intensity, as a function of independent variable x, representing distance from the light source. A beacon is lit at night in a eld, measured to have a luminous intensity of 1500 candela as measured at the source (i. e. from a distance of zero). 400 m, the intensity is measured to be 220 candela: determine the value of the extinction coe cient b for the air in this eld. 2: the average human can no longer detect light from a source when the intensity of the light drops to 2% of the intensity as measured at the source. Give your answer to the nearest metre: a simple hot water tank can be modeled by the following rst-order di erential equation: c dt dt.
