Physics · Unit 1 · Ionising radiation and nuclear reactions · Nuclear model and stability
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A sample contains \(8.0 \times 10^{15}\) undecayed nuclei of a radioactive isotope at \(t = 0\). After \(45\) minutes, \(1.0 \times 10^{15}\) undecayed nuclei remain. Which option best describes the half-life of this isotope?
A research team monitored the decay of a radioactive isotope over several weeks. The table below shows their measurements. Describe the concept of half-life, using evidence from the data to support your response.
A medical team uses technetium-99m (⁹⁹ₘTc) for diagnostic imaging. The isotope is delivered to the hospital at 8:00 am with an activity of 800 MBq. By 2:00 pm the same day, the activity has decreased to 100 MBq. Describe the concept of half-life and explain how it accounts for the change in activity observed between 8:00 am and 2:00 pm.
A sample of radioactive isotope X initially contains 800 g of the isotope. After 12 hours, 100 g of isotope X remains. Describe the concept of half-life and identify the half-life of isotope X.