1266_Physics ProblemsTechnical Physics

1266_Physics ProblemsTechnical Physics - Chapter 45 P45.37...

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Chapter 45 607 P45.37 (a) Starting with N = 0 radioactive atoms at t = 0, the rate of increase is (production – decay) dN dt RN =− λ so dN R N dt bg . The variables are separable. dN dt Nt = zz 00 : F H G I K J = 1 ln R t so ln R t F H G I K J and R e t F H G I K J = . Therefore, 1 −= R Ne t N R e t 1 ej . (b) The maximum number of radioactive nuclei would be R . Additional Problems P45.38 (a) Suppose each 235 U fission releases 208 MeV of energy. Then, the number of nuclei that must have undergone fission is N == × × total release energy per nuclei J 208 MeV J MeV nuclei 51 0 160 10 15 10 13 13 24 af . .. (b) mass nuclei 6.02 10 nuclei mol g mol kg 23 = × × F H G I K J 235 0 6 24 . . P45.39 (a) At 6 10 8 × K, the average kinetic energy of a carbon atom is 3 2 15 862 10 6 10 8 10 58 4 kT B eV K K eV × = × a f e j Note that 6 10 8 × K is about 6 36 2 = times larger than 1 5 10 7 . × K , the core temperature of the Sun. This factor corresponds to the higher potential-energy barrier to carbon fusion
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This note was uploaded on 12/15/2011 for the course PHY 203 taught by Professor Staff during the Fall '11 term at Indiana State University .

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