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NEET 2026 (Re-neet) · Nuclear Reactions & Q-value

Nuclear Reactions & Q-value question from NEET 2026 (Re-neet)

Q2NEET 2026 · RE-NEETMedium

Nuclear Reactions & Q-value

Consider the following nuclear reaction

238U⟶234Th+4He{}^{238}\text{U} \longrightarrow {}^{234}\text{Th} + {}^{4}\text{He}

Take masses of 238U,234Th{}^{238}\text{U}, {}^{234}\text{Th} and 4He{}^{4}\text{He} as 238.050u,234.043u238.050\text{u}, 234.043\text{u} and 4.003 u, respectively. The QQ value for the reaction, in keV, is:

[Given: 1u=931.5 MeV c−21\text{u} = 931.5\text{ MeV c}^{-2} ]

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Answer: (b)

  1. Δm=238.050−(234.043+4.003)=0.004 u\Delta m = 238.050 - (234.043 + 4.003) = 0.004\ \text{u}
  2. Q=0.004×931.5=3.726 MeVQ = 0.004 \times 931.5 = 3.726\ \text{MeV}
  3. So the answer is (b) 3726 keV3726\ \text{keV}.
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