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JEE Main 2022 (28 Jul, Shift 2) · Law of Radioactive Decay

Law of Radioactive Decay question from JEE Main 2022 (28 Jul, Shift 2)

Q39JEE Main 2022 · 28 JUL · SHIFT 2Easy

Law of Radioactive Decay

A radioactive sample decays 78\frac{7}{8} times its original quantity in 15 minutes. The half-life of the sample is

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Answer: (a)

  1. If 78\frac{7}{8} decays, 18\frac{1}{8} remains, i.e. 3 half-lives.
  2. 3T1/2=15 min⇒T1/2=5 min3T_{1/2} = 15\text{ min} \Rightarrow T_{1/2} = 5\text{ min}.
  3. So the answer is (a) 5 min.
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