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

Which of the following statements is correct?

The minimum kinetic energy needed by an alpha particle to cause the nuclear reaction ${ }_{7}^{16} N +{ }_{2}^{4} He \rightarrow{ }_{1}^{1} H +{ }_{8}^{19} O$ in a laboratory frame is $n$ (in $MeV$). Assume that ${ }_{7}^{16} N$ is at rest in the laboratory frame. The masses of ${ }_{7}^{16} N, { }_{2}^{4} He, { }_{1}^{1} H$ and ${ }_{8}^{19} O$ can be taken to be $16.006 \ u, 4.003 \ u, 1.008 \ u$ and $19.003 \ u$,respectively,where $1 \ u = 930 \ MeV/c^2$. The value of $n$ is. . . . .

Fast neutrons can be easily slowed down by:

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 an atomic bomb,the energy is released due to