The graph of binding energy per nucleon against nucleon number (A) rises steeply for light
Nuclear & Particle Physics - OCR A-Level Physics
- The graph of binding energyThe capacity to do work. Measured in joules (J). per nucleonThe binding energyThe capacity to do work. Measured in joules (J).The energyThe capacity to do work. Measured in joules (J). required to completely separate a nucleus into its individual protons and neutrons. Equal to the mass defectThe difference between the total mass of the individual nucleons and the actual mass of the nucleus. This mass is converted to binding energy. multiplied by c². of a nucleus divided by its nucleon number (mass number). Higher values indicate greater nuclear stability. against nucleon number (A) rises steeply for light nuclei, peaks at iron-56, and then gradually decreases.
- FusionTwo light nuclei combine to form a heavier nucleus, releasing energy (binding energy per nucleon increases).: light nuclei (A < 56) combine to form a heavier nucleus with higher binding energy per nucleonThe binding energyThe energy required to completely separate a nucleus into its individual protons and neutrons. Equal to the mass defectThe difference between the total mass of the individual nucleons and the actual mass of the nucleus. This mass is converted to binding energy. multiplied by c². of a nucleus divided by its nucleon number (mass number). Higher values indicate greater nuclear stability.. The increase in binding energy per nucleonThe binding energyThe energy required to completely separate a nucleus into its individual protons and neutrons. Equal to the mass defectThe difference between the total mass of the individual nucleons and the actual mass of the nucleus. This mass is converted to binding energy. multiplied by c². of a nucleus divided by its nucleon number (mass number). Higher values indicate greater nuclear stability. is released as kinetic energyThe energy an object possesses due to its motion..
- FissionA heavy nucleus splits into two smaller nuclei plus neutrons, releasing energy (binding energy per nucleon increases).: heavy nuclei (A > 56) split into lighter fragments with higher binding energy per nucleonThe binding energy of a nucleus divided by its nucleon number (mass number). Higher values indicate greater nuclear stability.. The increase in binding energy per nucleon is released as kinetic energyThe energy an object possesses due to its motion..
- Both processes move nuclei towards iron-56 on the curve - towards greater stability.
- Energy $released = (total binding energy$ of products) - (total binding energy of reactants).
Examiner Tips and Tricks
- When calculating energy released in fission or fusion, find the total binding energy (not per nucleon) for all reactants and all products.
- Energy $released = BE(products) - BE(reactants)$.
- If positive, energy is released.