Neco 2025 Physics Question 7

Practice objective / multiple choice question 7 from the 2025 Neco Physics examination.

Neco 2025 Physics Objective / Multiple Choice Hard Difficulty

Question 7 NECO • 2025 • PHYSICS • objective

A sample contains \(1.0\times10^{6}\) atoms of a radioactive isotope A that decays to isotope B with a half‑life of 8 min. Isotope B is itself radioactive and decays to a stable nucleus with a half‑life of 2 min. Initially only A is present. (a) At what time after the start does the activity of isotope B reach its maximum? (b) What is that maximum activity in decays per second? (Assume the decay constants are \(\lambda_{A}=\ln2/8\) min\(^{-1}\) and \(\lambda_{B}=\ln2/2\) min\(^{-1}\).)

A. 5.33 min, 1.0×10^3 s^{-1}

Correct Answer B. 5.33 min, 9.1×10^2 s^{-1}

C. 6.00 min, 1.2×10^3 s^{-1}

D. 4.00 min, 7.5×10^2 s^{-1}

Correct Answer

Correct Option:

5.33 min, 9.1×10^2 s^{-1}

This is Neco 2025 Physics Question 7. It is one of the objective questions from the 2025 Neco Physics examination.

Difficulty level: Hard .

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