In nuclear fission,the percentage of mass converted into energy is about: (in $\%$)

Which of the following statement$(s)$ is/are correct?
$(1)$ The rest mass of a stable nucleus is less than the sum of the rest masses of its constituent nucleons.
$(2)$ The rest mass of a stable nucleus is greater than the sum of the rest masses of its constituent nucleons.
$(3)$ Nuclear fusion involves the fusion of two light nuclei to form a heavier nucleus.
$(4)$ Nuclear fission involves the release of energy by the splitting of a heavy nucleus.

The energy liberated per nuclear fission is $200 \; MeV$. If $10^{20}$ fissions occur per second,the amount of power produced will be:

In the given nuclear reaction
${ }_{4}^{9} Be+{ }_{2}^{4} He \rightarrow{ }_{6}^{12} C+X$
$X$ represents $\qquad$

$A$ certain mass of Hydrogen is changed to Helium by the process of fusion. The mass defect in the fusion reaction is $0.02866 \, u$. The energy liberated per $u$ is ........... $MeV$. (Given $1 \, u = 931 \, MeV$)

Which of the following are suitable for the fusion process?