Q 21 :

The binding energy for the following nuclear reactions are expressed in MeV.

He23+n01He24+20 MeV

He24+n01He25-0.9 MeV

If X3,X4,X5 denote the stability of He23,He24 and He25 respectively, then the correct order is:             [2026]

  • X4>X5>X3

     

  • X4<X5<X3

     

  • X4>X5<X3

     

  • X4=X5=X3

     

(1)

BEHe4-BEHe3=20 MeV  (1)

BEHe5-BEHe4=-0.9 MeV  (2)

From eq (1) & (2)

BEHe4>BEHe5>BEHe3

X4>X5>X3



Q 22 :

The average energy released per fission for the nucleus of U92235 is 190 MeV. When all the atoms of 47 g pure U92235 undergo fission process, the energy released is α×1023 MeV. The value of α is ______.

(Avogadro Number =6×1023 per mole)  [2026]



(228)

Total number of U-235 atoms is

47 g=47235 moles=15 moles

  Total energy released=15×6×1023×190 MeV

=228×1023 MeV