Final answer:
Nuclear fission is the process where a heavy nucleus absorbs a neutron, becomes unstable, and splits into smaller nuclei along with free neutrons and a large amount of energy. This reaction can generate electricity in nuclear power plants or cause explosions in nuclear weapons. A chain reaction of fission can occur if there is enough material, known as the critical mass.
Step-by-step explanation:
The process in which a nucleus breaks apart into two or more fragments, releasing vast amounts of energy, is known as nuclear fission. This is a type of radioactive decay where a heavy nucleus, such as uranium-235, absorbs a neutron and becomes so unstable that it splits into two smaller nuclei (fission fragments), along with a few free neutrons and a significant amount of energy. The energy released is due to the conversion of a small amount of the mass from the original nucleus into energy, as described by Einstein's famous equation E=mc2.
In nuclear power plants, the energy from fission is harnessed to generate electricity. In nuclear weapons, the rapid release of energy from fission leads to an explosion. The fission process can become self-sustained as the neutrons produced can induce further fissions in a chain reaction, which requires a certain amount of material known as the critical mass. Besides producing energy, nuclear fission can also create isotopes of elements that can have various applications, including in medicine.
The reaction can be represented by the equation n+AX → FF1 + FF2 + xn, where 'n' represents a neutron, 'AX' the target nucleus, 'FF1' and 'FF2' are the daughter nuclei (or fission fragments), and 'x' is the number of neutrons produced.