The half life period of a radioactive substance is 60 days. The time taken for 7/8 th of its original mass to disintegrate will be: (a) 120 days (b) 130 days (c) 180 days (d) 20 days

Answer: (c). 7/8 disintegrated means 1/8 left, i.e. 3 half-lives. t = 3 × 60 = 180 days. So the answer is (c) 180 days.

The half life period of a radioactive substance is 60 days. The time… | JEE Main 2022 (28 Jul, Shift 1)

Q40JEE Main 2022 · 28 JUL · SHIFT 1Easy

Law of Radioactive Decay

The half life period of a radioactive substance is 60 days. The time taken for $\frac{7}{8}$ th of its original mass to disintegrate will be:

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Answer: (c)

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