1265_Physics ProblemsTechnical Physics

1265_Physics ProblemsTechnical Physics - 606 Applications...

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606 Applications of Nuclear Physics Section 45.7 Uses of Radiation P45.34 The initial specific activity of 59 Fe in the steel, Rm bg 0 4 6 20 0 0200 kg 100 3 70 10 1 370 10 == × F H G I K J . . . . µµ µ Ci Ci kg Bq Ci Bq kg . After 1 000 h, R m R m ee t = F H G I K J = × −× −− 0 6 640 10 1000 6 3 70 10 1 95 10 41 λ .. . Bq kg Bq kg h h ej . The activity of the oil, R oil Bq liter 50 liters Bq = F H G I K J = 800 60 0 68 6 7 . (. ) . . Therefore, m R in oil oil 7 Bq Bq kg kg × 86 195 10 445 10 6 5 . . . . So that wear rate is 5 . × kg 1000 h 4.45 10 kg h 8 . P45.35 The half-life of 14 O is 70.6 s, so the decay constant is = ln ln . . 22 70 6 000982 12 T s s 1 . The 14 O nuclei remaining after five min is NN e e t = × 0 10 300 8 10 5 26 10 af . . s s 1 . The number of these in one cubic centimeter of blood is ′= F H G I K J F H G I K J 100 526 10 2000 263 10 85 . . . . cm total vol. of blood cm cm 33 3 and their activity is RN =′ = × = × 0 009 82 2 63 10 2 58 10 10 53 3 . s Bq ~ Bq 1 e j . P45.36 (a) The number of photons is 10 104 962 10 4 3 MeV MeV . . . Since only 50% of the photons are detected, the number of 65 Cu nuclei decaying is twice this value, or 1 92 10 4 . × . In two half- lives, three-fourths of the original nuclei decay, so
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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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