Question

Does fusion or fission produce more energy?

Answer 1

Nuclear Fusion: It's the process by which two or lighter nuclei fuse to form a heavier nucleus, and energy is released as a result of the mass defect. For instance, when four hydrogen nuclei combine to produce a helium nucleus, energy is released.
Nuclear Fission: It's the process in which a heavier nucleus splits into two or lighter nuclei, releasing energy due to a mass defect. When attacked with a neutron, Uranium$235$ separates into Barium $141$, Krypton $92$, three free neutrons, and energy is liberated.

Complete step by step solution:
Binding energy is the key to comprehending this. The combined mass of protons and neutrons in a nucleus is always less than the combined mass of the same number of unbound protons and neutrons when they are bound together by a strong force.
The mass difference between two light nuclei is transformed into energy when they are fused to form a heavier nucleus. This implies that the nucleus must be broken apart with the same amount of energy.
The issue is that fusing Hydrogen into Helium produces a lot of energy. The energy released by fusing heavier elements is lower.
Iron and heavier element nuclei take more energy to fuse, thus fusion reactions consume rather than generate energy.
Fission produces more energy in heavier elements than iron. When a big nucleus splits into smaller nuclei, energy is released.
Certain elements, such as Uranium-$235$, are relatively easy to fission.
So, fusion creates more energy when light elements are included, while fission provides more energy when heavy ones are involved.

Note: The energy released by a single uranium fission reaction is around $210$ MeV, or around $1$ MeV per nucleon.
From hydrogen to nickel- $62$, fusing releases around $8$ MeV per nucleon fused.
The Coulomb repulsion is used in fission, which is somewhat overcome by the strong nuclear force.
Due to the strong nuclear force, fusion releases binding energy, which is often more than repulsion for light nuclei.