Answer: eta × epsilon × p × f.
- A eta × epsilon × p × f
- B A × B × C × D as generally observed
- C n × p × f × e in typical laboratory settings
- D power × time under usual circumstances
Correct answer: A. eta × epsilon × p × f
Explanation: Four-factor formula (infinite medium): k∞ = eta × epsilon × p × f where eta = reproduction factor, epsilon = fast fission factor, p = resonance escape probability, f = thermal utilization.
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.