Waec Model Questions Vol1 2019 Physics Question 21
Practice objective / multiple choice question 21 from the 2019 Waec Model Questions Vol1 Physics examination.
A rock sample contains two uranium isotopes: \(^{238}\text{U}\) with a half‑life of \(4.5\times10^{9}\) years and \(^{235}\text{U}\) with a half‑life of \(7.04\times10^{8}\) years. Let the initial numbers of atoms be \(N_{0,238}\) and \(N_{0,235}\) respectively. After exactly \(1.0\times10^{9}\) years the measured activity of \(^{238}\text{U}\) is twice that of \(^{235}\text{U}\). Determine the original ratio \(N_{0,238}:N_{0,235}\). Give your answer as a decimal to two significant figures.
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About This Question
This is Waec Model Questions Vol1 2019 Physics Question 21. It is one of the objective questions from the 2019 Waec Model Questions Vol1 Physics examination.
Difficulty level: Hard .
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