11.1. Atoms, nuclei and radiation
A subsection of Physics, 9702, through 11. Particle physics
Listing 10 of 202 questions
One possible nuclear fission reaction is 92 U + 1 0 n 56 Ba + 92 36 Kr + 3 1 0 n + energy. Barium-141 (141 56 Ba) and krypton-92 (92 36 Kr) are both β-emitters. Barium-141 has a half-life of 18 minutes and a decay constant of 6.4 × 10–4 s–1. The half-life of krypton-92 is 3.0 seconds. State what is meant by decay constant. A mass of 1.2 g of uranium-235 undergoes this nuclear reaction in a very short time (a few nanoseconds). Calculate the number of barium-141 nuclei that are present immediately after the reaction has been completed. number = Using your answer in , calculate the total activity of the barium-141 and the krypton-92 a time of 1.0 hours after the fission reaction has taken place. activity = Bq
9702_w13_qp_43
THEORY
2013
Paper 4, Variant 3
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