A nucleus X with mass number A and atomic number Z has mass M(A, Z). Mₚ and Mₙ are the free proton and neutron masses. Express its binding energy.
Options

Question

A nucleus X with mass number A and atomic number Z has mass M(A, Z). Mₚ and Mₙ are the free proton and neutron masses. Express its binding energy.

G1 Physics · Accepted Answer

A separated nucleon assembly has rest mass ZMₚ + (A − Z)Mₙ. The bound nucleus has less rest mass, M(A, Z). Their mass difference is Δm = ZMₚ + (A − Z)Mₙ − M(A, Z). Hence BE = Δmc². Final answer: Option A.