0654.P5.2.03 — Know that radioactive decay is a change in 4 Use decay equations, using nuclide notation, an unstable nucleus that can result in the to show: past paper questions
Real questions on 0654.p5.2.03 — know that radioactive decay is a change in 4 use decay equations, using nuclide notation, an unstable nucleus that can result in the to show
The newest 17 of 17 written questions. Open one to see it on the real paper.
- 0973/31 · May/June 2026 · Q9c(i)[2]
(i) 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 [2]
See it on the paper → - 0973/31 · May/June 2026 · Q9c(ii)[1]
Strontium-90 decays by B-emission. State the charge on a f-particle.
See it on the paper → - 0973/31 · May/June 2026 · Q9c(iv)[1]
(iv) State the names of two other types of radiation emitted when radioactive isotopes decay. .......... .......... .......... .......... eeeeeettettetttees [1]
See it on the paper → - 0973/42 · May/June 2026 · Q12a(iii)[1]
This isotope undergoes nuclear fission. Describe the process of nuclear fission.
See it on the paper → - 0973/31 · May/June 2025 · Q9c(iii)[2]
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 → - 0973/41 · May/June 2024 · Q6b(ii)[1]
Another isotope of chlorine is chlorine‑36 which is unstable. Fig. 6.2 shows how the number of undecayed nuclei in a sample changes over time. 800 700 600 500 number of undecayed nuclei in sample 400 300 200 100 0 0 200 400 600 800 time / thousand years Fig. 6.2 Use Fig. 6.2 to determine the half‑life of chlorine‑36. h...
See it on the paper → - 0973/41 · October/November 2023 · Q3b(ii)[2]
A 160 g sample of barium-141 has a half-life of 18 minutes. Calculate the time it will take for the mass of barium-141 in the sample to decrease to 10 g. time = minutes
See it on the paper → - 0973/31 · May/June 2023 · Q6b(iii)[3]
The half-life of plutonium-239 is 24 000 years. A sample of nuclear fuel contains 6.0 g of plutonium-239. Calculate the mass of plutonium-239 remaining after 72 000 years. mass = g
See it on the paper → - 0973/31 · October/November 2022 · Q3c[2]
Technetium-99 is a radioactive material. The half-life of technetium-99 is 6 hours. Calculate the percentage of technetium-99 remaining in a sample after 24 hours. percentage =
See it on the paper → - 0973/41 · October/November 2022 · Q12b[2]
The radioactive isotope uranium-238 decays into the isotope thorium-234 by emitting an α-particle. Use the correct nuclide notation to complete the decay equation for uranium-238. 238 92 U 234 Th + α
See it on the paper → - 0973/31 · May/June 2022 · Q6c(ii)[2]
The half-life of iodine-131 is 8 days. A sample of iodine-131 is left for 16 days. The mass of iodine-131 remaining is 0.05 g. Calculate the mass of iodine-131 in the sample at the start. mass = g
See it on the paper → - 0973/31 · May/June 2021 · Q12b(ii)[1]
The half‑life of uranium‑235 is 704 million years. A sample of uranium‑235 has a mass of 0.1 g. Calculate how many grams of uranium‑235 will remain in the sample after 704 million years. mass of uranium‑235 remaining = g
See it on the paper → - 0973/32 · May/June 2021 · Q12b(iii)[2]
Plutonium‑239 has a half‑life of 24 000 years. A sample of plutonium‑239 has a mass of 800 g. Calculate the mass of plutonium‑239 remaining after 48 000 years. mass = g
See it on the paper → - 0973/41 · May/June 2020 · Q9c(ii)[2]
A sample of I-123 contains 8 × 10 14 atoms. Sometime later 6 × 10 14 atoms have decayed. Calculate the time needed for this number of atoms to decay. time = hours
See it on the paper → - 0973/42 · May/June 2020 · Q6a(ii)[2]
Plutonium-239 has a half-life of 24 000 years. 2 kg of plutonium-239 is sealed in a lead container. Calculate the mass of plutonium-239 remaining after 120 000 years. mass = kg
See it on the paper → - 0973/41 · May/June 2019 · Q9d[2]
Alpha radiation is one form of ionising radiation. An isotope of plutonium, 239 94 Pu, decays by alpha emission to produce an isotope of uranium. Use the correct nuclide notation to write a symbol equation for this decay process. 239 94 Pu +
See it on the paper → - 0973/42 · May/June 2019 · Q9c[3]
An isotope of strontium, strontium-89, is used in the treatment of bone cancer in hospitals. Strontium-89 has a half-life of 50 days. A sample of this isotope contains 4 × 10 14 atoms. Some time later 3 × 10 14 atoms have decayed. Calculate the time needed for this number of atoms to decay. Show your working. time = da...
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What examiners said
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, 0973/31 Q9(c)(iii) (Cambridge)
The majority of candidates attempted to calculate the time taken for the mass of barium-141 to decrease by 10 g. These candidates showed clear steps in their calculations, but some gave their final answer as the mass left rather than the time taken. A few candidates tried unsuccessfully to calculate the time taken by using proportion rather than halving the mass four times from 160 g to 10 g.
— Examiner report, October/November 2023, 0973/41 Q3(b)(ii) (Cambridge)
This calculation was not well answered. A few candidates determined that 72 000 years was 3 halflives but were unable to do anything with the 3 apart from divide it into 6.0.
— Examiner report, May/June 2023, 0973/31 Q6(b)(iii) (Cambridge)
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