Assertion: Heavy water is a better moderator than normal water.
Reason: Heavy water absorbs neutrons more efficiently than normal water.

The energy released when $\frac{7}{17.13} \text{ kg}$ of $^7_3\text{Li}$ is converted into $^4_2\text{He}$ by proton bombardment is $\alpha \times 10^{32} \text{ eV}$. The value of $\alpha$ is . . . . . . . (Nearest integer) (Mass of $^7_3\text{Li} = 7.0183 \text{ u}$, mass of $^4_2\text{He} = 4.004 \text{ u}$, mass of proton $= 1.008 \text{ u}$, $1 \text{ u} = 931 \text{ MeV/c}^2$, and Avogadro number $N_A = 6.0 \times 10^{23} \text{ mol}^{-1}$)

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 $Z$.

The minimum frequency of a photon required to break a particle of mass $15.348 \ amu$ into $4 \ \alpha$ particles is . . . . . . $kHz$.
[Mass of $He$ nucleus = $4.002 \ amu$, $1 \ amu = 1.66 \times 10^{-27} \ kg$, $h = 6.6 \times 10^{-34} \ J \cdot s$ and $c = 3 \times 10^8 \ m/s$]

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. . . . .

In nuclear fission,the fission reaction proceeds with a projectile. Which of the following suits the best?