A certain radioactive isotope placed near a Geiger counter registers 160 counts per second. 32 hours later, the counter registers 10 counts per second. What is the half-life of the isotope?
A. 8 hours
B. 16 hours
C. 24 hours
D. 32 hours
E. none of the above
E. none of the above
The half-life is 2 hours. Here is my reasoning. If you cut 160 in half you will have 80.
1/2 of 80 = 40. 1/2 of 40 = 20. 1/2 of 20 = 10. We repeated this process 4 times. Four half-
lives have elapsed. [ Eight hours divided by 4, equals 2 hour.
]
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jeifunk|Points 6281|
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Asked 9/7/2012 10:04:54 AM
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