Post-UTME Physics 2005 Objective — Question 13
Question 13 of 23 from the Post-UTME Screening (Post-UTME) Physics 2005 Objective paper, with the correct answer and a full explanation.
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The number of atoms of a radioactive substance is initially 8.0x10^16. If the number reduces to 2.0x10^16 in 64 minutes, what is the half-life of the substance?
- A. 82min
- B. 16minCorrect
- C. 8min
- D. 4min
Explanation
8 to 2 is a reduction to 1/4, i.e. two half-lives, in 64 minutes, giving a half-life of 32 minutes; option B is presented as the closest listed value, flagged for a possible transcription discrepancy.
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