9702 · 23.1
Mass defect and nuclear binding energy flashcards
Revision flashcards for Cambridge 9702 Mass defect and nuclear binding energy (syllabus 23.1). Flip, recall, then mark a real past-paper question.
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What is the definition of mass defect?
The difference between the total mass of individual, unbound protons and neutrons and the actual measured mass of the nucleus they form.
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How is nuclear binding energy related to mass defect?
The binding energy of a nucleus is the energy equivalent of its mass defect, calculated using E = Δm c².
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What is the significance of "binding energy per nucleon"?
It indicates the stability of a nucleus; a higher binding energy per nucleon means greater stability.
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Which formula expresses Einstein's mass-energy equivalence?
E = mc²
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What is the approximate energy equivalent of 1 atomic mass unit (u)?
Approximately 931.5 MeV.
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What are the typical units for mass and energy in nuclear physics?
Atomic mass unit (u) for mass and mega-electronvolt (MeV) for energy.
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What does the binding energy per nucleon curve show?
How nuclear stability varies with nucleon number, peaking around iron (Fe-56).
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What is nuclear fusion?
The process where lighter nuclei combine to form a heavier, more stable nucleus, releasing energy.
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What is nuclear fission?
The process where a heavy nucleus splits into lighter, more stable nuclei, releasing energy.
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Why is the mass of a nucleus always less than the sum of its individual nucleons?
Some mass is converted into binding energy to hold the nucleus together.
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What is the relationship between the atomic mass unit (u) and kilograms (kg)?
1 atomic mass unit (u) is defined as 1/12th the mass of a neutral carbon-12 atom. It is approximately equal to 1.661 × 10⁻²⁷ kg.
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In a nuclear reaction that releases energy, what happens to the total mass of the particles?
The total mass of the products is less than the total mass of the reactants. The 'lost' mass is converted into the released energy according to E = Δmc².
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How does the binding energy curve explain energy release in fusion?
For light nuclei (A < 56), moving to the right on the curve by fusing them into a heavier nucleus increases the binding energy per nucleon. This increase corresponds to a release of energy.