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JAMB Physics 1987 Question 50

Question 50

Radioactivity and Nuclear Physics

A radioactive sample initially contains N atoms. After three half-lives the number of atoms that have disintegrated is

  1. A.N/8
  2. B.3N/8
  3. C.5N/8
  4. D.7N/8
Show the answer and explanation

Answer: D (7N/8)

Explanation

After three half-lives N/8 atoms are left undecayed, so N − N/8 = 7N/8 have disintegrated.