A factory buys 100 kg of a radioactive chemical with a half-life of 5 years which decays to a stable compound. How much of the chemical will still be radioactive in 10 years time?
Correct answer: B. 25 kg
- A. None
- B. 25 kg
- C. 50 kg
- D. 75 kg
Explanation
The chemical has a half life of 5 years, so in 10 years time 2 half lives will have elapsed. 100/2= 50 kg after 1 half life 50/2=25 kg remains after 2 half lives.
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Atomic nuclei contain protons and neutrons, with nuclear size, mass defect and binding energy describing their stability. The work covers alpha, beta and gamma decay, decay equations, half-life and decay rate, along with radiation safety and medical applications such as imaging, radiotherapy and tracers.
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