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JAMB Physics 1995 Question 49

Question 49

Radioactivity and Nuclear Physics

The half-life of a radioactive element is 9 days. What fraction of atoms has decayed in 36 days?

  1. A.1/16
  2. B.1/4
  3. C.1/2
  4. D.15/16
Show the answer and explanation

Answer: D (15/16)

Explanation

36 days is 4 half-lives, so (½)4 = 1/16 remains. The fraction decayed is 1 − 1/16 = 15/16.