Binding energy

Binding energy is the energy required to disassemble a whole into separate parts. A bound system has a lower potential energy than its constituent parts; this is what keeps the system together; it corresponds to a positive binding energy.

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At the nuclear level, binding energy is derived from the strong nuclear force and is the energy required to disassemble a nucleus into neutrons and protons. At the atomic level, binding energy is derived from electromagnetic interaction and is the energy required to disassemble an atom into electrons and a nucleus. In astrophysics, gravitational binding energy of a celestial body is the energy required to disassemble it into space debris, not to be confused with the gravitational potential energy to separate e.g. a celestial body and a satellite to infinite distance, keeping each intact.

Related Topics:
Strong nuclear force - Electromagnetic interaction - Gravitational binding energy - Gravitational potential energy

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Because a bound system is at a lower energy level, its mass must be less than its unbound constituents. Nuclear binding energy can be computed from the difference in mass of a nucleus, and the sum of the mass of the neutrons and protons that make up the nucleus. Once this mass difference (also called the mass defect) is known, Einstein's formula (E = mc²) can then be used to compute the binding energy of any nucleus.

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The energy given off during either nuclear fusion or nuclear fission is the difference between the binding energies of the fuel and the fusion or fission products.

Related Topics:
Nuclear fusion - Nuclear fission

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