Discussion
Experimentally it is observed that neutron (n)-proton(p) system (deuteron) is bound, but the proton-proton and neutron-neutron systems are not bound. This is due to :
Answer: C
The difference is due to Pauli's principle.
The nuclear force is spin dependent: it is strong enough to bind two nucleons only in the spin-triplet state (S = 1). The deuteron's ground state is exactly this, an L = 0, S = 1 state of a neutron and a proton, which are different particles and face no restriction.
Two protons or two neutrons are identical fermions, so their total wave function must be antisymmetric. In the lowest, L = 0 state the space part is symmetric, which forces the spin part to be the antisymmetric singlet (S = 0), and the singlet force is too weak to bind. So the Pauli principle keeps p-p and n-n out of the one state that binds.
The nuclear force itself is charge independent to a good approximation, so 'unequal nuclear force' is not the reason, and charge only adds Coulomb repulsion for p-p, which cannot explain why n-n is unbound. Angular momentum is conserved throughout.
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development