Neco 2017 Physics Question 12

Practice objective / multiple choice question 12 from the 2017 Neco Physics examination.

Neco 2017 Physics Objective / Multiple Choice Hard Difficulty
Question 12 NECO • 2017 • PHYSICS • objective

A sealed source contains \(2.0\times10^{20}\) atoms of isotope A (α emitter, half‑life \(30\) min, energy per decay \(5.0\) MeV) and the same number of isotope B (β emitter, half‑life \(2\) h, energy per decay \(1.2\) MeV). The source is left undisturbed for \(3\) h. (i) Calculate the total energy (in joules) released during this period, assuming that only \(80\%\) of the β‑particle energy is absorbed in the source. (ii) Determine the activity (in becquerels) of isotope B at the end of \(3\) h.

Answer Options

Correct Answer A. Total energy ≈ 1.78×10^8 J; Activity of B ≈ 6.8×10^15 Bq
B. Total energy ≈ 1.2×10^8 J; Activity of B ≈ 5.0×10^15 Bq
C. Total energy ≈ 1.78×10^7 J; Activity of B ≈ 6.8×10^14 Bq
D. Total energy ≈ 2.3×10^8 J; Activity of B ≈ 8.5×10^15 Bq
Correct Answer
A
Correct Option:
Total energy ≈ 1.78×10^8 J; Activity of B ≈ 6.8×10^15 Bq

About This Question

This is Neco 2017 Physics Question 12. It is one of the objective questions from the 2017 Neco Physics examination.

Difficulty level: Hard .

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