Answer: becquerel.
- A curie
- B becquerel
- C roentgen
- D gray
Correct answer: B. becquerel
Explanation: Activity in SI is measured in becquerel (Bq), one disintegration per second. The curie is the older, larger unit.
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.