By which process is the energy released from the Sun?

$U^{235}$ nuclear reactor generates energy at a rate of $3.70 \times 10^7 \text{ J/s}$. Each fission liberates $185 \text{ MeV}$ of useful energy. If the reactor has to operate for $144 \times 10^4 \text{ s}$, then the mass of the fuel needed is (Assume Avogadro's number $= 6 \times 10^{23} \text{ mol}^{-1}$, $1 \text{ eV} = 1.6 \times 10^{-19} \text{ J}$) (in $\text{ kg}$)

In the proton-proton cycle, four hydrogen nuclei combine to release energy of ....... $MeV$.

$A$ neutron strikes a ${ }_{92}^{235}U$ nucleus and as a result ${ }_{38}^{93}Kr$ and ${ }_{56}^{140}Ba$ are produced along with:

Choose the correct option to complete the net effect of the fusion reaction that occurs in the Sun: $4_1^1H + 2e^- \rightarrow$ . . . . . . $+ 2\nu + 6\gamma +$ . . . . . .

Under certain circumstances,a nucleus can decay by emitting a particle more massive than an $\alpha$-particle. Consider the following decay processes:
$_{88}^{223} Ra \rightarrow _{82}^{209} Pb + _{6}^{14} C$
$_{88}^{223} Ra \rightarrow _{86}^{219} Rn + _{2}^{4} He$
Calculate the $Q$-values for these decays and determine that both are energetically allowed.