State the principle of an atomic bomb and identify the nuclear process that occurs within it.

If the binding energy per nucleon for a deuteron is $1.112 \, MeV$ and for an $\alpha$-particle is $7.07 \, MeV$,then for the reaction $2 \, (_1H^2) \rightarrow _2He^4 + Q$,the value of $Q$ is .......... $MeV$.

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:

Mention the use of controlled nuclear fission. Mention the use of uncontrolled nuclear fission.

Suppose India had a target of producing by $2020\; AD$, $200,000\; MW$ of electric power, ten percent of which was to be obtained from nuclear power plants. Suppose we are given that, on an average, the efficiency of utilization (i.e., conversion to electric energy) of thermal energy produced in a reactor was $25\%$. How much amount of fissionable uranium would our country need per year by $2020$? Take the heat energy per fission of $^{235}_{92}U$ to be about $200\; MeV$.

Assertion: Energy is released when heavy nuclei undergo fission or light nuclei undergo fusion.
Reason: For heavy nuclei,binding energy per nucleon increases with increasing $Z$,while for light nuclei,it decreases with increasing $Z$.