Consider the following nuclear reaction : $^{238}\text{U} \rightarrow ^{234}\text{Th} + ^4\text{He}$. Take masses of $^{238}\text{U}$, $^{234}\text{Th}$ and $^4\text{He}$ as $238.050 \text{ u}$, $234.043 \text{ u}$ and $4.003 \text{ u}$, respectively. The $Q$ value for the reaction, in $\text{keV}$, is : [Given : $1 \text{ u} = 931.5 \text{ MeV/c}^2$]

Assuming the experimental mass of $^{12}_{6}C$ as $12 \text{ u}$, the mass defect of $^{12}_{6}C$ atom is . . . . . . $\text{u}$. (Mass of proton $= 1.00727 \text{ u}$, mass of neutron $= 1.00866 \text{ u}$).

In the nuclear process $n \to p + e^- + \bar{\nu}$,if the masses of proton,neutron,and electron are $1.6725 \times 10^{-27} \ kg$,$1.6747 \times 10^{-27} \ kg$,and $9 \times 10^{-31} \ kg$ respectively,then the energy released is ...... $MeV$.

$A$ plot of the number of neutrons $(N)$ against the number of protons $(Z)$ for stable nuclei exhibits upward deviation from linearity for atomic number $Z > 20$. For an unstable nucleus having an $N/Z$ ratio less than $1$,the possible mode$(s)$ of decay is(are):
$(A)$ $\beta^{-}$-decay ($\beta$ emission)
$(B)$ Orbital or $K$-electron capture
$(C)$ Neutron emission
$(D)$ $\beta^{+}$-decay (positron emission)

The figure shows a plot of binding energy per nucleon $E_b$ against the nuclear mass $M$. $A, B, C, D, E, F$ correspond to different nuclei. Consider four reactions:
$(i) \, A + B \to C + \varepsilon$
$(ii) \, C \to A + B + \varepsilon$
$(iii) \, D + E \to F + \varepsilon$
$(iv) \, F \to D + E + \varepsilon$
where $\varepsilon$ is the energy released. In which reactions is $\varepsilon$ positive?

The rest mass of the deuteron,${}_1^2H$,is equivalent to an energy of $1876 \, MeV$. The rest mass of a proton is equivalent to $939 \, MeV$ and that of a neutron is $940 \, MeV$. $A$ deuteron may disintegrate into a proton and a neutron if it: