Question

Describe how energy is produced in a nuclear reaction. Distinguish between fission and fusion.

Short answer

Energy is produced in a nuclear reaction through the process of fission, where a heavy nucleus splits into two smaller ones, or fusion, where two lighter nuclei combine to form a larger one. The significant distinction between fission and fusion is that fission involves splitting of an atomic nucleus, while fusion is about combining two lighter nuclei to form a heavier. Fusion releases more energy but requires very high temperatures to initiate.

Step-by-step solution

Understanding Nuclear Reactions

A nuclear reaction generates energy through the process of fission or fusion. In fission, a heavy nucleus splits into two or more smaller nuclei, while in fusion, two light nuclei combine to form a larger one. The energy is produced as a result of mass change into energy under Einstein's mass-energy equivalence, E=mc^2.

Elucidating Nuclear Fission

In nuclear fission, the nucleus of an atom divides into two smaller fragments. This process emits a large quantity of energy as well as free neutrons and gamma photons. Uranium-235 and Plutonium-239 are most commonly used for fission as they are fissile, i.e., they can sustain a nuclear chain reaction.

Elucidating Nuclear Fusion

Nuclear fusion involves the combination of lighter nuclei to form a heavier nucleus. This process, too, releases energy, generally more significant than that from nuclear fission. The sun and other stars accomplish nuclear fusion of hydrogen to form helium.

Distinguish between Fission and Fusion

The main difference between fission and fusion is that fission is the splitting of an atomic nucleus, while fusion is the combination of two lighter atomic nuclei to form a heavier nucleus. Fusion releases more energy than fission. However, it is harder to achieve because it requires very high temperatures (millions of degrees) to overcome the electrostatic repulsion between the two positively charged nuclei.