The newest 20 of 28 written questions. Open one to see it on the real paper.
Asample of strontium-90 has a mass of 2.0g. The half-life of strontium-90 is 29 years. Calculate the mass of strontium-90 remaining after 116 years. MASS 9
See it on the paper →Strontium-90 decays by B-emission. State the charge on a f-particle.
See it on the paper →State the names of two other types of radiation emitted when radioactive isotopes decay. eeeeeettettetttees
See it on the paper →This isotope undergoes nuclear fission. Describe the process of nuclear fission.
See it on the paper →Define the term half-life.
See it on the paper →Initially a sample of 19789 Au has a mass of 280 g. mass = g Calculate the mass remaining after 8.1 days.
See it on the paper →New elements form during radioactive decay. 21 0 Po is radioactive. It decays by emitting an alpha particle. 8 4 Complete the equation for this nuclear decay. 21 0 Po 8 Pb + α
See it on the paper →Initially a sample of 21804 Po has a mass of 560 g. The half-life of 21804 Po is 3.1 minutes. Calculate the mass of 21804 Po remaining after 12.4 minutes. mass = g
There was no consistent approach to this question with candidates performing a wide variety of incorrect calculations. Candidates need a clear understanding of a half-life in order to complete these manipulations and it was evident that many were trying to multiply by 0.25 to somehow determine the answer.
— Examiner report, May/June 2025, 0654/31 Q9(c)(iii) (Cambridge)
Candidates gave the incorrect nuclide notation for the beta particle. Some candidates reversed the values of 0 and –1, whilst some gave the nuclide notation for an alpha particle.
— Examiner report, February/March 2025, 0654/42 Q11(a)(i) (Cambridge)
The correct answer of 0.4 was commonly seen. The incorrect value of 92.8 was commonly seen.
— Examiner report, February/March 2025, 0654/42 Q11(a)(ii) (Cambridge)
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The half-life of iridium-192 is 74 days. Calculate the time taken for the mass of iridium-192 to decay to 25% of its original mass. time taken = days
See it on the paper →Complete the equation for this nuclear decay.
See it on the paper →The mass of 38 Sr in a sample is 1.6 mg. mass mg 90 Calculate the mass of 38 Sr isotope remaining after 58 years.
See it on the paper →The fuel rod contains uranium-235 ( 235 92 U). Uranium-235 decays by alpha emission. Use correct nuclide notation to complete the decay equation for uranium-235. 235 92 U Th + α
See it on the paper →100 g of plutonium-239 is sealed in a lead container and left for 96 000 years. Calculate the mass of plutonium-239 remaining after 96 000 years. mass = g
See it on the paper →Complete the word equation to show the decay of a nucleus of plutonium-239. plutonium-239 +
See it on the paper →Plutonium-239 decays by alpha emission. The decay product is uranium-235. Write the word equation for this decay process.
See it on the paper →How many half-lives of the isotope elapse in 45 hours?
See it on the paper →Tc has a half‑life of 6 hours. 43 Calculate the percentage of 99 43 Tc remaining in a sample after 24 hours. percentage remaining = %
See it on the paper →Tc is produced in hospitals from molybdenum‑99 ( 99 Mo). 42 43 Use the correct nuclide notation to complete the decay equation for molybdenum‑99. 99 Mo 42 99 Tc 43 +
See it on the paper →241 When americium‑241 ( 95 Am) decays it emits an alpha particle. Use the correct nuclide notation to complete the decay equation for americium‑241. 241 Am Np + α 93
See it on the paper →Plutonium-239 (Pu-239) is the nuclear fuel used by the submarine. Pu-239 has a half life of 24 000 years. A small sample of Pu-239 has a mass of 1.0 g. Calculate the mass of Pu-239 remaining after 96 000 years. mass = g
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