The newest 20 of 77 written questions. Open one to see it on the real paper.
Define the mass defect of a nucleus.
See it on the paper →Use the data in Table 9.1 to explain why thorium-228 is an a-emitter and not a emitter or a B* emitter.
See it on the paper →Calculate the energy, in MeV, released by the a-decay of one thorium-228 nucleus. Give your answer to three significant figures. energy = . . MeV
See it on the paper →Define the binding energy of a nucleus.
See it on the paper →Show that the binding energy of the $He nuclide is 4.54 x 10-'2J.
See it on the paper →Define the mass defect of a nucleus.
See it on the paper →Use the data in Table 9.1 to explain why thorium-228 is an a-emitter and not a emitter or a B* emitter.
See it on the paper →Calculate the energy, in MeV, released by the a-decay of one thorium-228 nucleus. Give your answer to three significant figures. energy = . . MeV
See it on the paper →Calculate the mass, in u, of the uranium-238 nuclide. Give your answer to five decimal places. mass = u
See it on the paper →State what is meant by the mass defect of a nucleus.
See it on the paper →Table 9.1 nuclide nuclide mass / u 2 1 H 2.013 553 4 2 He 4.001 505 Calculate the energy released in the formation of 1.00 mol of helium-4. energy = J Table 9.1 shows the masses of the nuclides involved in this reaction. 4 2 He. 2 2 1 H + 1 H (b) The nuclear fusion reaction for the formation of helium-4 from deuterium...
See it on the paper →Calculate the mass, in u, of the uranium-238 nuclide. Give your answer to five decimal places. mass = u
See it on the paper →Radioactive decay is a spontaneous process. State the meaning, in this context, of the term spontaneous.
See it on the paper →Complete Table 10.1 to give expressions, in terms of either or both of A and T, for the quantities indicated for each of the samples. Table 10.1 sample half-life decay constant initial activity X 4A Y A initial number of nuclei
See it on the paper →Determine, in terms of T, the time at which the two samples will have equal activities. time = T
See it on the paper →A radiation detector is placed near to one of the samples in (b). Explain why the count rate measured by the detector is less than the activity of the sample.
See it on the paper →Complete the equation for this decay. 88 Q 222 4 R + 2 α
See it on the paper →By considering momentum, calculate the speed of nucleus R after the decay. speed = m s –1
See it on the paper →State three quantities that are conserved during the decay.
See it on the paper →Describe the differences between nuclear fission and nuclear fusion.
See it on the paper →The majority of candidates gave the two correct values. The most common incorrect value of the nucleon number of Q was 218 and the most common incorrect value of the proton number of R was 90.
— Examiner report, February/March 2025, 9702/22 Q7(a) (Cambridge)
The stronger candidates were able to apply the conservation of momentum to the correct nuclei in this decay. A common error was to use the proton number instead of the mass number for both particles. Many weaker candidates attempted to include particle Q and assigned it a non-zero speed, meaning they could make little progress. A significant number of the weakest candidates seemed unaware of how t...
— Examiner report, February/March 2025, 9702/22 Q7(b) (Cambridge)
Very few candidates managed to give three quantities that are conserved. ‘Momentum’ and ‘charge’ were the most common correct answers. ‘Mass’ and ‘energy’ were the most common incorrect answers. A small number of candidates scored a mark for mass-energy. Very few candidates gave ‘nucleon number’ or ‘proton number’ despite having (usually correctly) applied the conservation of both quantities in 7(...
— Examiner report, February/March 2025, 9702/22 Q7(c) (Cambridge)
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