Gce Model Questions Vol1 2025 Physics Question 11
Practice objective / multiple choice question 11 from the 2025 Gce Model Questions Vol1 Physics examination.
A sample contains a radioactive isotope A that decays with a half‑life of 5 min. In each decay, 70 % of the nuclei transform into a detectable daughter B, while the remaining 30 % become an undetectable daughter C. After 20 min the measured activity due to B is \(5.0\times10^{3}\ \text{s}^{-1}\). Assuming the decay constant remains unchanged, calculate the initial number of nuclei of isotope A present in the sample. Give your answer as an integer (rounded to the nearest whole number).
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About This Question
This is Gce Model Questions Vol1 2025 Physics Question 11. It is one of the objective questions from the 2025 Gce Model Questions Vol1 Physics examination.
Difficulty level: Hard .
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