The average number of prompt neutrons produced per fission of ${\mathrm{U}}^{235}$ is 

(1) More than 5         

(2) 3 to 5

(3) 2 to 3                 

(4) 1 to 2

In an atomic bomb, the energy is released due to

(1) Chain reaction of neutrons and ${}_{92}{}^{235}\mathrm{U}$
(2) Chain reaction of neutrons and ${}_{92}{}^{288}\mathrm{U}$
(3) Chain reaction of neutrons and ${}_{92}{}^{240}\mathrm{P}$
(4) Chain reaction of neutrons and ${}_{92}{}^{286}\mathrm{U}$

The energy liberated on complete fission of 1 kg of ${}_{{}_{}{}^{}92}{}^{235}\mathrm{U}$ is (Assume 200 MeV energy is liberated on fission of 1 nucleus) 

(1) $8.2\times {10}^{10} \mathrm{J}$                           

(2) $8.2\times {10}^9 \mathrm{J}$

(3) $8.2\times {10}^{13} \mathrm{J}$                           

(4) $8.2\times {10}^{16} \mathrm{J}$

The nuclear reaction ${}_1{}^2\mathrm{H}+{}_1{}^2\mathrm{H}\to {}_2{}^4\mathrm{He}$ (mass of deuteron = 2.0141 a.m.u. and mass of He = 4.0024 a.m.u.) is

(1) Fusion reaction releasing 24 MeV energy

(2) Fusion reaction absorbing 24 MeV energy

(3) Fission reaction releasing 0.0258 MeV energy

(4) Fission reaction absorbing 0.0258 MeV energy

In the following reaction the value of ‘X’ is  
${}_7{}^{14}\mathrm{N}+{}_2{}^4\mathrm{He}\to \mathrm{X}+{}_1{}^1\mathrm{H}$

(1) ${}_8{}^{17}\mathrm{N}$             

(2) ${}_8{}^{17}\mathrm{O}$

(3) ${}_7{}^{16}\mathrm{O}$             

(4) ${}_7{}^{16}\mathrm{N}$

The binding energy of nucleus is a measure of its

(1) Charge             

(2) Mass

(3) Momentum       

(4) Stability

Heavy water is

(1) Water at 4$°\mathrm{C}$

(2) Compound of deuterium and oxygen

(3) Compound of heavy oxygen and heavy hydrogen

(4) Water in which soap does not lather

If M is the atomic mass and A is the mass number, packing fraction is given by:
(1) $\frac{\mathrm{A}}{\mathrm{M}-\mathrm{A}}$           

(2) $\frac{\mathrm{A}-\mathrm{M}}{\mathrm{A}}$
(3)$\frac{M}{\mathrm{M}-\mathrm{A}}$            

(4) $\frac{\mathrm{M}-\mathrm{A}}{\mathrm{A}}$

${\mathrm{M}}_{\mathrm{p}}$ denotes the mass of a proton and ${\mathrm{M}}_{\mathrm{n}}$ that of a neutron. A given nucleus of binding energy B contains Z protons and N neutrons. The mass M(N, Z) of the nucleus is given by:    (c is the velocity of light) 

(1) $\mathrm{M}(\mathrm{N}, \mathrm{Z})={\mathrm{NM}}_{\mathrm{n}}+{\mathrm{ZM}}_{\mathrm{p}}-{\mathrm{Bc}}^2$

(2) $\mathrm{M}(\mathrm{N}, \mathrm{Z})={\mathrm{NM}}_{\mathrm{n}}+{\mathrm{ZM}}_{\mathrm{p}}+{\mathrm{Bc}}^2$

(3) $\mathrm{M}(\mathrm{N}, \mathrm{Z})={\mathrm{NM}}_{\mathrm{n}}+{\mathrm{ZM}}_{\mathrm{p}}-\mathrm{B}/{\mathrm{c}}^2$

(4) $\mathrm{M}(\mathrm{N}, \mathrm{Z})={\mathrm{NM}}_{\mathrm{n}}+{\mathrm{ZM}}_{\mathrm{p}}+\mathrm{B}/{\mathrm{c}}^2$