What happens to the mass number and the atomic number of an element when it emits \(\gamma\text{-}\)radiation?

1.	mass number decreases by four and atomic number decreases by two.
2.	mass number and atomic number remain unchanged.
3.	mass number remains unchanged while the atomic number decreases by one.
4.	mass number increases by four and the atomic number increases by two.

The energy required in \(\text{MeV/c}^2 \) to separate \({ }_8^{16} \mathrm{O}\) into its constituents is:
(Given: mass defect for \({ }_8^{16} \mathrm{O}=0.13691~ \text{amu}\))
1. \(127.5\)
2. \(120.0\)
3. \(222.0\)
4. \(119.0\)

The energy equivalent of \(0.5\) g of a substance is:
1. \(4.5\times10^{13}\) J
2. \(1.5\times10^{13}\) J
3. \(0.5\times10^{13}\) J
4. \(4.5\times10^{16}\) J

In the nuclear decay given below: 
${}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{X}\to {}_{\mathrm{Z}+1}{}^{\mathrm{A}}\mathrm{Y}\to {}_{\mathrm{Z}-1}{}^{\mathrm{A}-4}\mathrm{B}\to {}_{\mathrm{Z}-1}{}^{\mathrm{A}-4}\mathrm{B}$
the particles emitted in the sequence are:

The mass of a \({}_{3}^{7}\mathrm{Li}\) nucleus is \(0.042\) u less than the sum of the masses of all its nucleons. The binding energy per nucleon of the \({}_{3}^{7}\mathrm{Li}\) nucleus is near:
1. \(4.6\) MeV
2. \(5.6\) MeV
3. \(3.9\) MeV
4. \(23\) MeV