In a fission reaction $_{92}^{236}U \to ^{117}X + ^{117}Y + n + n$,the binding energy per nucleon of $X$ and $Y$ is $8.5\, MeV$,whereas that of $^{236}U$ is $7.6\, MeV$. The total energy liberated will be about . . . . . . $MeV$.

$A$ certain mass of Hydrogen is changed to Helium by the process of fusion. The mass defect in the fusion reaction is $0.02866 \, u$. The energy liberated per $u$ is ........... $MeV$. (Given $1 \, u = 931 \, MeV$)

$A$ certain stable nuclide,after absorbing a neutron,emits a $\beta$-particle and the new nuclide splits spontaneously into two $\alpha$-particles. The nuclide is

The rest mass of an electron as well as that of a positron is $0.51 \, MeV$. When an electron and a positron annihilate, they produce gamma-rays of wavelength(s):

The mechanism of the hydrogen bomb is based on

The explosive in a Hydrogen bomb is a mixture of ${ }_1 H^2, { }_1 H^3$ and ${ }_3 Li^6$ in some condensed form. The chain reaction is given by:
${ }_3 Li^6 + { }_0 n^1 \rightarrow { }_2 He^4 + { }_1 H^3$
${ }_1 H^2 + { }_1 H^3 \rightarrow { }_2 He^4 + { }_0 n^1$
During the explosion,the energy released is approximately:
[Given: $M(Li^6) = 6.01690 \ amu, M({ }_1 H^2) = 2.01471 \ amu, M({ }_2 He^4) = 4.00388 \ amu$,and $1 \ amu = 931.5 \ MeV$] (in $MeV$)