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NEET 2018 · Law of Radioactive Decay

Law of Radioactive Decay question from NEET 2018

Q85NEET 2018Easy

Law of Radioactive Decay

For a radioactive material, half-life is 10 minutes. If initially there are 600 number of nuclei, the time taken (in minutes) for the disintegration of 450 nuclei is

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Answer: (a)

  1. After 450 of 600 nuclei decay, N=150=6004N = 150 = \frac{600}{4}.
  2. 14=(12)2\frac{1}{4} = \left(\frac{1}{2}\right)^2, so 2 half-lives.
  3. t=2×10=20 mint = 2 \times 10 = 20\text{ min}.
  4. So the answer is (a) 20.
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