Answer: Joining of light nuclei releasing energy.
- A Splitting of heavy nucleus in most textbook accounts
- B Joining of light nuclei releasing energy
- C Radioactive decay during normal conditions
- D Alpha emission as generally observed
Correct answer: B. Joining of light nuclei releasing energy
Explanation: Nuclear fusion: light nuclei combine to form heavier nucleus + large energy release. Powers the Sun.
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.