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********Please CHECK WRONG ANSWERS before responding*********
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****ANSWER is NOT 4.678 seconds/0.0779 minutes****
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Update:
Since the daughter's half-life is much smaller than the parent's half-life, the daugther reaches the parent's activity only asymptotically over several half-lives.
Activity of daughter after n half-lives: ARb = ASr(1−(1/2)n)
You need to find the value of n such that ARb/ASr>=0.99
Note: You do not have to find the exact time when ARb/ASr=0.99
Instead find the smallest value of the integer n such that, after n half-lives ARb/ASr>=0.99.
Please Check Wrong Answers Before Responding Answer Is Not 4 678 Seconds 0 0779 Minutes U 1 (29.81 KiB) Viewed 65 times
2) Suppose you have a sample with 100 mCi of 82 Sr. When will the activity of 82Rb reach over 99% of the activity of 82 Sr? 7.74e-11 Your submissions: 7.74e-11 X Computed value: 7. 7.7e-11 X Feedback: 4.68 IX 2.4e5 IX 0.07798 X 3) How much daught 7.8e-2 8.3 20 min Submit Help Xestion 1) will there be after 20 minutes? IX XmCi Submit O
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