Thermal neutrons can cause fission in

$A$ nuclear reactor generates power by fission of ${}_{92}U^{235}$ into two equal fragments of ${}_{46}Pd^{116}$ with the emission of two $\gamma$-rays of $5.2 \text{ MeV}$ each and three neutrons. The average binding energies per nucleon of ${}_{92}U^{235}$ and ${}_{46}Pd^{116}$ are $7.2 \text{ MeV}$ and $8.2 \text{ MeV}$ respectively. The usable energy released per fission event is ......... $\text{MeV}$.

Nuclear fusion is common to the pair:

Kinetic energy of the emitted $\alpha-$ particle in the $\alpha-$ decay of ${}_{88}^{226}Ra$ will be,.......... $MeV$ (where $m_{\alpha} = 4.00260 \, u$,$m({}_{88}^{226}Ra) = 226.02540 \, u$ and $m({}_{86}^{222}Rn) = 222.01750 \, u$).

Light energy emitted by stars is due to

The following is not used as a nuclear fuel.