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Nuclear Physics Homework
 250 g of I131 emits beta particles in its radioactive decay. Its half life
is 8 days. How much remains after 16 days? Write the decay equation. Ans: 62.5 g
 The half life of Sr90 is 28 years. If 60 g of Sr90 is found in a soil sample,
estimate the amount in the sample after 84 years. Write is decay equation (it
emits a beta particle). Ans: 7.5 g
 Sr82 has a half life of 25 days. If you begin with a 140 g sample, how
many days later will you only have 17.5 g? Ans: 75 d
 The half life of a certain isotope is 20 h. How much of an original sample of 320 g remains after 80 h? After 5 d? Ans: 20 g; 5 g










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