TRB PG Assistant - Liquid drop model, shell model, collective models, nuclear fission One Line Questions & Answers

1. The energy released per fission event for Uranium-235 is approximately: — 200 MeV

2. The semi-empirical mass formula's Coulomb term is proportional to: — Z^2 / A^(1/3)

3. In the Nuclear Shell Model, nucleons are assumed to move in: — An average potential created by all other nucleons

4. Nuclear fission is a process where: — A heavy nucleus splits into two or more lighter nuclei

5. Nuclear fission can be controlled in a nuclear reactor by using: — A moderator to slow down neutrons and control rods to absorb them

6. Magic numbers in nuclear physics, such as 2, 8, 20, 28, 50, 82, and 126, correspond to: — Complete filled nucleon shells

7. The energy released during nuclear fission is primarily due to: — Conversion of mass into energy (E=mc^2)

8. The chain reaction in nuclear fission is sustained by: — Emitted neutrons

9. The concept of 'spin-orbit coupling' is crucial in the Shell Model for: — Predicting the order of energy levels

10. Spontaneous fission is a type of radioactive decay that occurs without: — External particle bombardment

11. The collective model explains the excitation of nuclei to higher energy states through: — Collective rotations and vibrations of the nucleus as a whole

12. In deformed nuclei, the Collective Model predicts energy levels that follow patterns characteristic of: — Rigid rotors

13. The collective model explains the energy levels of deformed nuclei by considering them as: — A quantum mechanical rotor

14. The Shell Model predicts that nuclei with a magic number of protons or neutrons are: — Spherical and have exceptionally high binding energies

15. The Collective Model describes nuclear shape oscillations and rotations as arising from: — The collective motion of nucleons as a fluid

16. The 'delayed neutrons' in fission are important for: — Controlling the chain reaction in reactors

17. Nuclear fission is most readily induced in nuclei that are: — Heavy and have a high neutron-to-proton ratio

18. The Collective Model combines aspects of which two simpler models? — Shell and Liquid Drop

19. Which model incorporates both individual particle motion and collective behavior of nucleons? — Collective Model

20. Which model is most suitable for understanding the excited states of even-even nuclei that show rotational bands? — Collective Model

21. The concept of nuclear 'magic numbers' provides strong evidence for the validity of the: — Shell Model

22. The collective model is particularly successful in describing the properties of nuclei that are: —

23. The 'prompt neutrons' emitted during fission are: — Neutrons emitted almost instantaneously with the fission event

24. Which aspect of nuclear structure is NOT well explained by the Liquid Drop Model? — Magic numbers and shell structure

25. Which of the following is NOT a direct consequence explained by the basic Liquid Drop Model? — Nuclear shell structure

26. The success of the Shell Model lies in its ability to explain: — Nuclear magic numbers

27. Which phenomenon is well explained by the Liquid Drop Model's semi-empirical mass formula? — Nuclear fission

28. The 'pairing energy' term in the semi-empirical mass formula favors: — Nuclei with an even number of protons and an even number of neutrons

29. In the context of nuclear fission, the 'fissile' nuclei are those that can undergo fission: — When bombarded by thermal (slow) neutrons

30. The volume energy term in the Liquid Drop Model suggests that binding energy is: — Proportional to A

31. Which particle is typically used to induce fission in heavy nuclei like Uranium? — Neutron

32. Which model treats the nucleus as a uniformly charged liquid drop? — Liquid Drop Model

33. A critical mass is the minimum amount of fissile material required to sustain a: — Nuclear chain reaction

34. The binding energy per nucleon in the Liquid Drop Model is primarily dependent on which terms? — Volume and surface effects

35. In the Liquid Drop Model, the surface energy term accounts for: — The reduced binding energy for nucleons at the nuclear surface.

36. The Coulomb energy term in the Liquid Drop Model represents: — The repulsive electrostatic force between protons.

37. The Shell Model of the nucleus is analogous to: — The Bohr model of the atom

38. The shell corrections to the Liquid Drop Model are important for understanding: — The stability of nuclei near magic numbers

39. In the context of the Shell Model, the 'j-j coupling' scheme describes: — The coupling of individual nucleon angular momenta (orbital + spin)

40. The 'asymmetry energy' term in the semi-empirical mass formula accounts for: — The difference in binding energy between protons and neutrons

41. The Liquid Drop Model explains nuclear fission as a process involving: — The oscillation of the nucleus to a point where the Coulomb forces overcome the surface tension

42. The Collective Model explains phenomena like: — Rotational and vibrational energy bands in deformed nuclei

43. The Collective Model can be viewed as an extension of the Shell Model that accounts for: — The cohesive behavior of the nucleus as a whole

44. The 'effective potential' experienced by a nucleon in the Shell Model is derived from: — The average interaction with all other nucleons

45. The fission barrier height can be estimated using: — The liquid drop model with corrections

46. The Liquid Drop Model's prediction of nuclear fission relies on the nucleus oscillating until: — The Coulomb repulsion overcomes the surface tension

47. Which of the following is a common fissile isotope of Uranium? — Uranium-235

48. Nuclear fission can be initiated by gamma rays, but this process, called photofission, typically requires: — High energy gamma rays

49. The semi-empirical mass formula, derived from the Liquid Drop Model, includes terms for: — Volume, surface, Coulomb, asymmetry, and pairing energies

Liquid drop model, shell model, collective models, nuclear fission - One Line Questions