ConceptModern Physics
← All conceptsMass-energy & binding energy
E=mc2, mass defect and binding energy, energy release in fission/fusion, recoil via momentum conservation
9 ways this goes wrong. Each one is a named misconception the questions are built to catch.
- BE per nucleon vs stability reversedAssociates higher binding energy per nucleon with less stability.→
- Binding energy adds massBelieves binding energy adds mass to the nucleus rather than corresponding to the missing mass defect.→
- E=mc2 drops the squareUses E=mc instead of E=mc2, omitting the squaring of the speed of light.→
- Energy from total mass not defectComputes released energy from the total nuclear mass rather than the small mass change/defect.→
- Fusion energy for heavy nucleiThinks fusion of heavy nuclei (or fission of light nuclei) releases energy, ignoring the iron-peak trend.→
- Mass defect sign reversedTakes the nucleus mass as larger than its separate nucleons, reversing the mass defect.→
- Recoil energy split equallySplits the released energy equally between the heavy daughter and light emitted particle, ignoring that the lighter particle carries far more kinetic energy.→
- Recoil ignores momentum conservationFinds a decay product's recoil speed without setting the daughter and emitted particle momenta equal and opposite from a nucleus at rest.→
- Total vs per-nucleon BE confusedCompares total binding energies to judge stability instead of binding energy per nucleon.→
