21.
Which of the following reactions violates lepton number conservation?

22.
Fission fragments are generally radioactive as

24.
The disintegration energy is defined to be the difference in the rest energy between the initial and final states. Consider the following process: $${}_{94}^{240}{\text{Pu}} \to {}_{92}^{236}{\text{U}} + {}_2^4{\text{He}}$$
The emitted α-particle has a kinetic energy 5.17 MeV. The value of the disintegration energy is

26.
The interaction potential between two quarks, separated by a distance r inside a nucleon can be described by (a, b and β are positive constants)

28.
According to the single particle nuclear shell model, the spin parity of the ground state of $${}_8^{17}O$$  is

29.
A ferromagnetic mixture of iron and copper having 75% atoms of Fe exhibits a saturation magnetization of 1.3 × 106 Am-1. Assume that the total number of atoms per unit volume is 8 × 1028 m-3. The magnetic moment of an iron atom in terms of the Bohr magneton is

30.
Which one of the following nuclear processes is forbidden?