As compared ${}_{12}\mathrm{C}$ atom, ${}_{14}\mathrm{C}$ atom has

(1) Two extra protons and two extra electrons

(2) Two extra protons but no extra electrons

(3) Two extra neutrons and no extra electrons

(4) Two extra neutrons and two extra electrons

If m, ${\mathrm{m}}_{\mathrm{n}}$ and ${\mathrm{m}}_{\mathrm{p}}$ are the masses of ${}_{\mathrm{Z}}\mathrm{X}_{\mathrm{A}}$ nucleus, neutron and proton respectively 

(1) $\mathrm{m}<\left(\mathrm{A}-\mathrm{Z}\right){\mathrm{m}}_{\mathrm{n}}+{\mathrm{Zm}}_{\mathrm{p}}$       

(2) $\mathrm{m}=\left(\mathrm{A}-\mathrm{Z}\right){\mathrm{m}}_{\mathrm{n}}+{\mathrm{Zm}}_{\mathrm{p}}$

(3) $\mathrm{m}=\left(\mathrm{A}-\mathrm{Z}\right){\mathrm{m}}_p+{\mathrm{Zm}}_{\mathrm{n}}$        

(4) $\mathrm{m}>\left(\mathrm{A}-\mathrm{Z}\right){\mathrm{m}}_{\mathrm{n}}+{\mathrm{Zm}}_{\mathrm{p}}$

On the bombardment of neutron with Boron. $\mathrm{\alpha }$-particle is emitted and product nuclei formed is

(1) ${}_6\mathrm{C}_{{}_{12}}$         

(2) ${}_3\mathrm{Li}_6$

(3) ${}_3\mathrm{Li}_7$           

(4) ${}_4\mathrm{Be}_9$

The average kinetic energy of the thermal neutrons is of the order of 

(1) 0.03 eV         

(2) 3 eV 

(3) 3 KeV           

(4) 3 MeV

Which of the following isotopes is normally fissionable ?

(1) ${}_{92}\mathrm{U}_{238}$             

(2) ${}_{93}\mathrm{Np}_{239}$

(3) ${}_{92}\mathrm{U}_{235}$             

(4) ${}_2\mathrm{He}_4$

The process by which a heavy nucleus splits into light nuclei is known as 

(1) Fission           

(2) $\mathrm{\alpha }$-decay

(3) Fusion             

(4) Chain reaction

The explosion of the atomic bomb takes place due to

1. Nuclear fission           

2. Nuclear fusion

3. Scattering               

4. Thermionic emission

Energy generation in stars is mainly due to

(1) Chemical reactions               

(2) Fission of heavy nuclei

(3) Fusion of light nuclei             

(4) Fusion of heavy nuclei

Fusion reaction is initiated with the help of 

(1) Low temperature         

(2) High temperature

(3) Neutrons                     

(4) Any particle