(a) In the fusion reactions taking place within core of sun, 4 hydrogen nuclei combines to form a helium nucleus with the release of 26 MeV of energy.
4

1

‌

1

H →

4

‌

2

He+2e+ + 26 MeV
Number of atoms in 1 kg of

1

‌

1

H ,
n =

1000g×6×1023

Atomic‌mass

=

1000g

1g

× 6 × 1023 = 6 × 1026 atoms
Energy released in the fusion of 1 kg of

1

‌

1

H,
E1 =

6×1026×26

4

MeV = 39 × 1026 MeV
(b) Energy released per fission of U-235 is 200 MeV.
Number of atoms in 1 kg of U-235,
n =

1000g×6×1023

235g

= 25.53 × 1023 atoms
Total energy released for fission of 1 kg of uranium,
E2 = 25.53 × 1023 × 200 MeV = 5.1 × 1026 MeV

E1

E2

=

39×1026

5.1×1026

= 7.65 = 8
So the energy released in fusion of 1 kg of Hydrogen is nearly 8 times the energy released in fission of 1 kg of uranium-235.