Nuclear constants: What is the energy equivalent of one atomic mass unit (1 amu) expressed in MeV (using E = m c^2)?

Introduction / Context:Mass–energy equivalence is central to nuclear physics. Converting atomic mass units (amu) into energy (MeV) allows quick estimation of binding energies, reaction Q-values, and decay energies.

Given Data / Assumptions:

• 1 amu ≈ 1.66054 × 10^−27 kg.
• Speed of light c ≈ 3.00 × 10^8 m/s.
• E = m * c^2.

Concept / Approach:Compute E for 1 amu and convert joules to electron-volts. The widely used constant is 1 amu ≈ 931 MeV of energy equivalent, which underpins tabulated nuclear masses and binding energies per nucleon (~8 MeV for medium-mass nuclei).

Step-by-Step Solution:E = m * c^2 = (1.66054 × 10^−27 kg) * (3.00 × 10^8 m/s)^2.E ≈ 1.494 × 10^−10 J.1 eV = 1.602 × 10^−19 J → E ≈ (1.494 × 10^−10) / (1.602 × 10^−19) eV ≈ 9.31 × 10^8 eV.Hence, E ≈ 931 MeV.

Verification / Alternative check:Handbooks and nuclear data tables consistently cite 1 amu ≈ 931 MeV (more precisely ~931.5 MeV).

Why Other Options Are Wrong:9.31 and 93.1 MeV are off by powers of ten; 9310 MeV is too large by a factor of 10.

Common Pitfalls:

• Confusing MeV with MeV/c^2 (a mass unit). 1 amu ≈ 931 MeV/c^2 as a mass; energy equivalent is 931 MeV.
• Rounding inconsistencies; 931 vs. 931.5 MeV are both acceptable approximations.

Final Answer:931 MeV