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

In the options given below, let $E$ denote the rest mass energy of a nucleus and $n$ a neutron. The correct option is:

The average number of prompt neutrons produced per fission of ${U^{235}}$ is

The $Q$ value of a nuclear reaction $A+b \rightarrow C+d$ is defined by $Q=\left[m_{A}+m_{b}-m_{C}-m_{d}\right] c^{2}$ where the masses refer to the respective nuclei. Determine from the given data the $Q$ value of the following reactions and state whether the reactions are exothermic or endothermic.
$(i) \;_{1}^{1} H+_{1}^{3} H \rightarrow_{1}^{2} H+_{1}^{2} H$
$(ii)\;_{6}^{12} C+_{6}^{12} C \rightarrow_{10}^{20} N e+_{2}^{4} H e$
Atomic masses are given to be:
$m(_{1}^{1}H) = 1.007825 \; u$
$m(_{1}^{2}H) = 2.014102 \; u$
$m(_{1}^{3}H) = 3.016049 \; u$
$m(_{6}^{12}C) = 12.000000 \; u$
$m(_{10}^{20}Ne) = 19.992439 \; u$
$m(_{2}^{4}He) = 4.002603 \; u$

What is the energy released by the fission of $1 \, g$ of $U^{235}$?

Explain the process of thermonuclear fusion as a source of energy in the Sun and stars.