If an electron and a positron annihilate, then the energy released is:
1. \(3.2\times 10^{-13}~\text{J}\)
2. \(1.6\times 10^{-13}~\text{J}\)
3. \(4.8\times 10^{-13}~\text{J}\)
4. \(6.4\times 10^{-13}~\text{J}\)

Fission of nuclei is possible because the binding energy per nucleon in them:

During negative $\mathrm{\beta }$-decay:

The mass of an $\mathrm{\alpha }$-particle is:

The Binding energy per nucleon of \(^{7}_{3}\mathrm{Li}\) and \(^{4}_{2}\mathrm{He}\) nucleon are \(5.60~\text{MeV}\) and \(7.06~\text{MeV}\), respectively. In the nuclear reaction \(^{7}_{3}\mathrm{Li} + ^{1}_{1}\mathrm{H} \rightarrow ^{4}_{2}\mathrm{He} + ^{4}_{2}\mathrm{He} +Q\), the value of energy \(Q\) released is:
1. \(19.6~\text{MeV}\)
 2. \(-2.4~\text{MeV}\)
 3. \(8.4~\text{MeV}\)
4. \(17.3~\text{MeV}\)

A nucleus \({ }_{{n}}^{{m}} \mathrm{X}\) emits one $\mathrm{}$\(\alpha\text -\text{particle}\) and two \(\beta\text- \text{particle}\) The resulting nucleus is:
1. \(^{m-}{}_n^6 \mathrm{Z} \)
2. \(^{m-}{}_{n}^{4} \mathrm{X} \)
3. \(^{m-4}_{n-2} \mathrm{Y}\)
4. \(^{m-6}_{n-4} \mathrm{Z} \)