(a) Write one nuclear fusion reaction.

(b) State the approximate value of energy released in the reaction mentioned in part (a).

(c) Give reason for the release of energy stated in part (b).

(a) A nuclear fusion reaction is given below:

$\begin{matrix} _{1}^{2}\text{H} & + & _{1}^{2}\text{H} & \longrightarrow & _{2}^{3}\text{He} & + & _{0}^{1}\text{n} & + & 3.3\text{ MeV} \ \footnotesize{\text{(deuterium)}} & & \footnotesize{\text{(deuterium)}} & & \footnotesize{\text{(helium isotope)}} & & \footnotesize{\text{(neutron)}} \end{matrix}$

$\begin{matrix} _{2}^{3}\text{He} & + & _{1}^{2}\text{H} & \longrightarrow & _{2}^{4}\text{He} & + & _{1}^{1}\text{H} & + & 18.3\text{ MeV} \ \footnotesize{\text{(helium isotope)}} & & \footnotesize{\text{(deuterium)}} & & \footnotesize{\text{(helium)}} & & \footnotesize{\text{(proton)}} \end{matrix}$

In this reaction, three deuterium nuclei fuse to form a helium nucleus.

(b) Approximately, 21.6 MeV energy is released in the reaction.

(c) When two deuterium nuclei fuse, 3.3 MeV energy is released and the nucleus of helium isotope (${}_2^3\text{He}${2}^{3}\text{He} ) is formed. This helium again gets fused with one deuterium nucleus to form a helium nucleus (${2}^{4}\text{He}$) and 18.3 MeV is released.