For a bound nucleus containing Z protons and N neutrons, which expression gives the mass defect?
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Question

For a bound nucleus containing Z protons and N neutrons, which expression gives the mass defect?

G1 Physics · Accepted Answer

The mass defect is the difference between the total mass of the separated free nucleons and the actual mass of the bound nucleus. Mass of separated nucleons: M(free) = Zmₚ + Nmₙ. Therefore, Δm = M(free) − M(nucleus) = Zmₚ + Nmₙ − M(nucleus). For a stable bound nucleus, Δm is positive. Correct option: B.