Which quantum phenomenon explains alpha particle decay from heavy nuclei despite the alpha particle having less energy than the nuclear Coulomb potential barrier height?
Answer and explanation
Correct answer: C. Quantum mechanical tunneling
- Step 1: In classical mechanics, a particle cannot cross a potential barrier higher than its kinetic energy. Step 2. In quantum mechanics, the wave function has a non-zero tail extending through the barrier, allowing finite probability of penetration (tunneling), as explained by George Gamow in 1928. Answer: Quantum mechanical tunneling. Why not the others: Photoelectric effect relates to photon-electron interactions; pair production requires photon energy > 1.022 MeV.
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