The quantity of uranium is 400g, the amount of uranium left after three half-lives is:
Correct answer: C. 50 g
- A. 12.5 g
- B. 25 g
- C. 50 g
- D. 100 g
Explanation
To calculate the amount of uranium left after three half-lives, you can use the formula:Final amount=Initial amount×(1/2 )number of half-livesGiven the initial amount of uranium is 400g, after three half-lives, the calculation would be:Final amount=400g×(1/2 )3 =400g×1/8 =50gSo, after three half-lives, 50 grams of uranium would remain.
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About Half-life and Rate of Decay
Half-life is the time required for half the unstable nuclei in a sample to decay, and it remains constant for a particular radioactive nuclide. Questions use the exponential decay law, decay constant, activity, remaining quantity and mean life. Radioactive decay is random for individual nuclei but predictable for large samples.
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