Answer: Ratio of neutrons in successive generations.
- A Number of neutrons per fission as frequently described
- B Ratio of neutrons in successive generations
- C Total energy per fission in most textbook accounts
- D Control rod position during normal conditions
Correct answer: B. Ratio of neutrons in successive generations
Explanation: Multiplication factor k = neutrons in next generation / neutrons in previous generation. k=1: critical, k>1: supercritical, k<1: subcritical.
Binding energy per nucleon rises sharply for light nuclei, peaks around iron-56 (the most stable nucleus), then slowly declines for heavier nuclei - which is exactly why fusing light nuclei or splitting heavy nuclei both release energy: each moves the products toward this stability peak.
Concept context
Radioactivity, nuclear reactions, fission, fusion, and binding energy.