HW10-19c-20 - 6-14 Binary Nuclear Reactions Chap. 6 (c) The...

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Unformatted text preview: 6-14 Binary Nuclear Reactions Chap. 6 (c) The earth is about Re = 93 X 106 mi = 1.50 X 1013cm from the sun. A sphere with this radius has a surface area of A = 47r ~ = 2.81 X 1027cm2. R The radiant power crossingthis spherical surface is P 8 or the energy flux per unit area is solarconstant= Ps 47rR2 e -2.81 -4 X 1026 W X 1027 cm2 = 0.142 W fcm2, Explain how electricity generated from hydroelectric power, wind turbines, coal-fired power plants, and nuclear power plants are all indirect manifestations of fusion energy generated in stars. Solution: Fusion reactions in stars (and our sun) result in radiant energy flowing into space. Solar energy absorbed and reflected by our atmosphere causes our weather. The heating of the atmosphere causesconvective currents or winds from which we can extract energy with wind turbines. The solar energy also causesthe water cycle in our atmosphere in which water is evaporated and, after condensing, falls as rain replenishing the rivers from which we obtain hydroelectric energy. Coal and all other fossil fuels are the fossilized remains of vegetation, which required sunlight to grow. Finally, when stars die, somebecomesupernovasand, during their brief explosive end, all the heavy elements, including uranium, are formed. The debris from suchnovasbecomespart of interstellar gas clouds and new stars and their planets that are eventually formed from these dust clouds. The uranium used in nuclear reactors was thus formed in stars. July 24, 2002 20. ...
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This note was uploaded on 02/01/2010 for the course ECE 4130 taught by Professor Cady during the Spring '06 term at Cornell University (Engineering School).

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