How long can an electric lamp of $100\; W$ be kept glowing by the fusion of $2.0\; kg$ of deuterium? Take the fusion reaction as $_{1}^{2} H + _{1}^{2} H \rightarrow _{2}^{3} He + n + 3.27\; MeV$.

In a nuclear fission reaction of an isotope of mass $M$,three similar daughter nuclei of the same mass are formed. The speed of a daughter nucleus in terms of mass defect $\Delta M$ will be:

$U^{235}$ 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 $\text{ kg}$)

What is a nuclear chain reaction? Explain the difficulties and their removal for its successful operation.

The phenomenon in which a proton flips is

In the fusion reaction,${ }_1 H^2+{ }_1 H^2 \rightarrow{ }_2 He^4+Q$,where $Q$ is the energy released. If $c$ is the speed of light and $m$ is the mass of each deuterium nucleus,then the mass of the helium nucleus formed is: