1 atomic mass unit is equal to 
(1) $\frac{1}{25}$ (mass of ${\mathrm{F}}_2$ molecules)
(2) $\frac{1}{14}$ (mass of ${\mathrm{N}}_2$ molecules)
(3) $\frac{1}{12}$ (mass of one C-atom)
(4) $\frac{1}{16}$ (mass of ${\mathrm{O}}_2$ molecules)

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

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

${\mathrm{M}}_{\mathrm{p}}$ 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) $\mathrm{M}(\mathrm{N},\hspace{0.17em}\mathrm{Z})={\mathrm{NM}}_{\mathrm{n}}+{\mathrm{ZM}}_{\mathrm{p}}-{\mathrm{Bc}}^2$

(2) $\mathrm{M}(\mathrm{N},\hspace{0.17em}\mathrm{Z})={\mathrm{NM}}_{\mathrm{n}}+{\mathrm{ZM}}_{\mathrm{p}}+{\mathrm{Bc}}^2$

(3) $\mathrm{M}(\mathrm{N},\hspace{0.17em}\mathrm{Z})={\mathrm{NM}}_{\mathrm{n}}+{\mathrm{ZM}}_{\mathrm{p}}-\mathrm{B}/{\mathrm{c}}^2$

(4) $\mathrm{M}(\mathrm{N},\hspace{0.17em}\mathrm{Z})={\mathrm{NM}}_{\mathrm{n}}+{\mathrm{ZM}}_{\mathrm{p}}+\mathrm{B}/{\mathrm{c}}^2$

Complete the reaction
$\mathrm{n}+{}_{92}{}^{235}\mathrm{U}\to {}_{56}{}^{144}\mathrm{Ba}+...+3\mathrm{n}$

1. ${}_{36}{}^{89}\mathrm{Kr}$      

2. ${}_{36}{}^{90}\mathrm{Kr}$

3. ${}_{36}{}^{91}\mathrm{Kr}$       

4. ${}_{36}{}^{92}\mathrm{Kr}$

The binding energy of nucleus is a measure of its

(1) Charge             

(2) Mass

(3) Momentum       

(4) Stability

The nucleus ${}_{92}{}^{234}\mathrm{U}$ splits exactly in half in a fission reaction in which two neutrons are released. The resultant nuclei are

(1) ${}_{46}{}^{116}\mathrm{Pd}$        

(2) ${}_{45}{}^{117}\mathrm{Rh}$

(3) ${}_{45}{}^{116}\mathrm{Rh}$       

(4) ${}_{46}{}^{117}\mathrm{Pd}$

A nucleus is bombarded with a high speed neutron so that resulting nucleus is a radioactive one. This phenomenon is called 

(1) Artificial radioactivity         

(2) Fusion

(3) Fission                               

(4) Radioactivity

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