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Radioactive Decay with Half-Life Concept

I need some help in determining the half-life:
1. A radioactive source has a half life of 74 days and an activity of 370 MBq. what was the activity 30 days ago?

2. A radioactive source has a half life of 60 days. what is the relative activity after one week?

3. An 11- Ci Ir- 192 source is recieved on August 20. Regulatory requirementss do not allow use of the source until its activity is 10 Ci or less. On what date will the source reach activity?

4. A patient had a 25- mCi I - 125 permanent seed implant 3 years ago. what is the activity now?

5. For a prostate seed implant, I- 125 seeds with an activity of .350 mCi are needed on the day of the implant. the seeds are to be delivered one week prior to the implant. what activity should the seeds have on the day of delivery?

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Solution Summary

The solution solves several problems involving the law of radioactive decay with step-by-step workings and all formulas and explanations are shown.