O-LevelPhysicsNuclear Physics5054/12 · Oct/Nov 2023 · Q391 Mark

The half-life of a radioactive isotope is 2.5 minutes. This isotope is the only radioactive isotope in a radioactive sample. Between time t = 0 and t = 7.5 minutes, the mass of this isotope in the sample decreases by 70 μg. What is the mass of this isotope at t = 0?

A75 μg

B80 μg

C210 μg

D560 μg

✓ Correct answer

B: 80 μg

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Topic: Nuclear Physics, O-Level Physics (syllabus 5054). Multiple choice, 1 mark.
Source: O-Level Physics, Oct/Nov 2023 Paper 1 Variant 2, question 39.

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