RE-NEET 2026 Physics Nuclear Reactions MCQ Question

✅ Ans: 4 → 3726 keV

Key Concept:

$$Q=(m_{\text{initial}}-m_{\text{final}})c^2$$ $$\Delta m=238.050-(234.043+4.003)$$ $$=0.004\,u$$

Using $1u=931.5\,MeV$:

$$Q=0.004\times931.5 =3.726\,MeV$$ $$\boxed{Q=3726\,keV}$$

❌ Why other options are wrong?

• 3730 ❌ → incorrect mass-defect conversion
• 3736 ❌ → arithmetic error
• 3740 ❌ → incorrect mass defect

📌 NCERT: “The energy equivalent of one atomic mass unit is about 931.5 MeV.”

🧠 NEET Trick: Mass defect → × 931.5 → MeV → ×1000 → keV.