What is the significance of a negative Q. value, and what is the Q. value for Be + He → C + 01n? (Masses: Be = 9.0122 u, He = 4.0026 u, C = 12.0000 u, 01n= 1.0087 u, 1 u = 931.5 MeV/c2 ).
Correct answer: A. Energy absorbed = 5.70 MeV
- A. Energy absorbed = 5.70 MeV
- B. Energy released = 5.70 MeV
- C. Energy absorbed = 6.70 MeV
- D. Energy released = 6.70 MeV
Explanation
Negative Q-value means the reaction is endothermic (absorbs energy). Calculation: Δm = 9.0122 + 4.0026 − (12 + 2×1.0087) = 0.0061 u; Energy = 0.0061 × 931.5 MeV ≈ 5.70 MeV.
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