Igcse Model Questions Vol1 2017 Physics Question 37

Practice objective / multiple choice question 37 from the 2017 Igcse Model Questions Vol1 Physics examination.

Igcse Model Questions Vol1 2017 Physics Objective / Multiple Choice Hard Difficulty
Question 37 IGCSE_MODEL_QUESTIONS_VOL1 • 2017 • PHYSICS • objective

A radioactive isotope A decays to isotope B with a half‑life of 8 min, and B subsequently decays to a stable isotope C with a half‑life of 2 min. Initially the sample contains 1000 atoms of A and none of B. After 10 min a detector records an activity of 120 decays s\(^{-1}\) from isotope B. (i) Determine the initial number of atoms of A present in the sample. (ii) If each decay of A releases 2.0 MeV and each decay of B releases 1.5 MeV, calculate the total energy released up to the 10 min moment in joules.

Answer Options

A. Initial atoms ≈ 1.2×10⁵; total energy ≈ 3.9×10⁻⁸ J
Correct Answer B. Initial atoms ≈ 1.6×10⁵; total energy ≈ 4.7×10⁻⁸ J
C. Initial atoms ≈ 2.0×10⁵; total energy ≈ 5.5×10⁻⁸ J
D. Initial atoms ≈ 1.6×10⁵; total energy ≈ 3.0×10⁻⁸ J
Correct Answer
B
Correct Option:
Initial atoms ≈ 1.6×10⁵; total energy ≈ 4.7×10⁻⁸ J

About This Question

This is Igcse Model Questions Vol1 2017 Physics Question 37. It is one of the objective questions from the 2017 Igcse Model Questions Vol1 Physics examination.

Difficulty level: Hard .

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