In a nuclear reactor, the main purpose of the moderator is to

For the following two nuclear reactions,the atomic number and mass number of nuclei $X$ and $Y$ are respectively:
$(I) \, _{92}^{235}U + _{0}^{1}n \rightarrow X + _{35}^{85}Br + 3 _{0}^{1}n$
$(II) \, _{3}^{6}Li + _{1}^{2}H \rightarrow Y + _{2}^{4}He$

Match the nuclear processes given in column $I$ with the appropriate option$(s)$ in column $II$.

Column $I$	Column $II$
$A$. Nuclear fusion	$P$. Absorption of thermal neutrons by ${}_{92}^{235}U$
$B$. Fission in a nuclear reactor	$Q$. ${}_{27}^{60}Co$ nucleus
$C$. $\beta$-decay	$R$. Energy production in stars via hydrogen conversion to helium
$D$. $\gamma$-ray emission	$S$. Heavy water
	$T$. Neutrino emission

Two lighter nuclei combine to form a comparatively heavier nucleus by the relation given below:
${ }_{1}^{2} X +{ }_{1}^{2} X ={ }_{2}^{4} Y$
The binding energies per nucleon of ${ }_{1}^{2} X$ and ${ }_{2}^{4} Y$ are $1.1 \, MeV$ and $7.6 \, MeV$ respectively. The energy released in this process is in $MeV$.

If in a nuclear fission,a piece of uranium of mass $0.5\, g$ is lost,the energy obtained in $kWh$ is

The control rod in a nuclear reactor is made of