Answer: 1/sqrt(Q) (inverse square root of Q-value).
- A The absolute temperature of the decaying sample
- B 1/sqrt(Q) (inverse square root of Q-value)
- C The mass number A of the parent nucleus alone
- D The atomic number Z of the parent nucleus squared
Correct answer: B. 1/sqrt(Q) (inverse square root of Q-value)
Explanation: Geiger-Nuttall law: log(lambda) = A + B/sqrt(E<sub>alpha</sub>) where E<sub>alpha</sub> is alpha energy. Explains dramatic variation of half-lives with energy.
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.