Q. A nucleus ᴬZX has mass represented by M(A, Z). If Mp and Mn denote the mass of proton and neutron respectively and B.E. the binding energy in MeV, then
A) B.E. = [ZMp + (A − Z)Mn − M(A, Z)]c²
B) B.E. = [ZMp + ZMn − M(A, Z)]c²
C) B.E. = M(A, Z) − ZMp − (A − Z)Mn
D) B.E. = [M(A, Z) − ZMp − (A − Z)Mn]c²
Explanation
[Solution from source] Binding energy is the mass defect times c²: B.E. = [ZMp + (A − Z)Mn − M(A, Z)]c². The expression without c² is a mass, not an energy, and the reversed sign would give a negative binding energy. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.