The example of nuclear fusion is

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 $MeV$.

Nuclear fission was discovered by

Explain an example in which heat transfer is necessary.

Heavy water is used as a moderator in a nuclear reactor. The function of the moderator is

The binding energy per nucleon of ${}_3^7Li$ and ${}_2^4He$ nuclei are $5.60 \, MeV$ and $7.06 \, MeV$, respectively. In the nuclear reaction ${}_3^7Li + {}_1^1H \to 2 \, {}_2^4He + Q$, the value of energy $Q$ released is ............ $MeV$.