Q 12-13-031JEE MainJEE Main 2026 (5 Apr, Shift 2)Easy
Assuming the experimental mass of $^{12}_6C$ as $12u$, the mass defect of $^{12}_6C$ atom is ______ $\text{MeV/c}^2$.
(Mass of proton $= 1.00727$u, mass of neutron $= 1.00866$u, $1\text{u} = 931.5\ \text{MeV/c}^2$ and c is the speed of the light in vacuum).
Answer: (B) $89.03$
Concept. Mass defect $=Zm_p+Nm_n-M$.
Step 1. Defect. $6(1.00727)+6(1.00866)-12=0.09558$ u.
Step 2. In MeV. $0.09558\times931.5=89.03$ MeV/$c^2$.
Answer. Option B.
Solution by Sreeraj P, M.Sc Physics
