Which of the following pairs of nuclei are isotones?

1. ${}_{34}{}^{74}\mathrm{Se},$ ${}_{31}{}^{71}\mathrm{Ca}$          

2. ${}_{42}{}^{92}\mathrm{Mo},$ ${}_{40}{}^{92}\mathrm{Zr}$

3. ${}_{38}{}^{81}\mathrm{Sr},$ ${}_{38}{}^{86}\mathrm{Sr}$             

4. ${}_{20}{}^{40}\mathrm{Ca},$ ${}_{16}{}^{32}\mathrm{S}$

Fusion reaction takes place at a higher temperature because:

After two alpha decays and four beta(-ve) decays, the atomic number:

The volume (V) of a nucleus is related to its mass (M) as:

1.  $V$ $\propto$ $M$

2.  $V$ $\propto$ $\frac{1}{M}$

3.  $V$ $\propto$ $M^3$

4.  $V$ $\propto$ $\frac{1}{M^3}$

If the density of gold nucleus is X, then the density of silver nucleus will be:

1.  2X

2. $\frac{X}{3}$

3.  4X

4.  X 

The binding energies of the nuclei A and B are E_a and E_b respectively. If three atoms of the element B fuse to give one atom of element A and an energy Q is released, then E_a, E_b and Q are related as:

1. E_a – 3E_b = Q

2. 3E_b – E_a = Q

3. E_a + 3E_b = Q

4. E_b + 3E_a = Q

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

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:

If M (A, Z), ${\mathrm{M}}_p$, and ${\mathrm{M}}_n$ denote the masses of the nucleus ${}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{X}$, proton, and neutron respectively in units of u (1 u = 931.5 MeV/c²) and BE represents its binding energy in MeV, then: