Nuclear fission is the process in which
- A. two light nuclei join to form a heavier one
- B. a heavy nucleus splits into two lighter nuclei, releasing energy and neutrons
- C. a nucleus emits an alpha particle
- D. an electron is captured by a nucleus
Explanation
Splitting a uranium 235 nucleus releases about 200 MeV together with two or three neutrons, and those neutrons can trigger further fissions in a chain reaction. Joining light nuclei is fusion, which powers the Sun and releases even more energy per unit mass. Both release energy because the products are more tightly bound than the reactants.