Answer: 1.022 MeV.
- A 0.511 MeV
- B 1.022 MeV
- C 2.044 MeV
- D 0.511 keV
Correct answer: B. 1.022 MeV
Explanation: Minimum energy for pair production = 2 × m<sub>e</sub> c² = 2 × 0.511 MeV = 1.022 MeV. Excess energy becomes kinetic energy of pair.
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.