Nuclear chemistry: decay modes, nuclear reactions, Q‑value, cross sections and photonuclear reactions - Question Bank

1. Which type of nuclear reaction involves the interaction of two nuclei to form a heavier nucleus?
A) Fission
B) Fusion
C) Alpha decay
D) Electron capture
2. What is the primary consequence of a nuclear reaction with a large positive Q-value?
A) Significant energy absorption
B) Significant energy release
C) No energy change
D) A change in the number of electrons
3. Photonuclear reactions are also known as:
A) Neutron capture
B) Photodisintegration
C) Alpha emission
D) Beta decay
4. The term 'cross section' in nuclear physics is analogous to:
A) The target area presented to an incident particle
B) The binding energy of the nucleus
C) The speed of the incident particle
D) The overall stability of the nucleus
5. A nuclear reaction that requires energy input to proceed is:
A) Exothermic
B) Endothermic
C) Isochoric
D) Isothermal
6. The 'decay modes' of a radioactive isotope describe:
A) The rate of decay
B) The pathways by which it transforms
C) The energy released
D) The emitted particles
7. What happens to the number of protons and neutrons in beta-plus decay?
A) Protons increase by 1, neutrons decrease by 1.
B) Protons decrease by 1, neutrons increase by 1.
C) Both remain unchanged.
D) Protons decrease by 1, neutrons increase by 1.
8. What happens to the number of protons and neutrons in beta-minus decay?
A) Protons increase by 1, neutrons decrease by 1.
B) Protons decrease by 1, neutrons increase by 1.
C) Both remain unchanged.
D) Protons decrease by 1, neutrons increase by 1.
9. Which of the following is a characteristic feature of photonuclear reactions?
A) Emission of neutrons or protons
B) Absorption of electrons
C) Generation of neutrinos
D) Formation of new elements through fusion
10. In nuclear reactions, 'cross section' is usually measured in units of:
A) meters squared
B) barns (1 barn = 10^-28 m^2)
C) electron volts
D) moles
11. What is the significance of the 'binding energy per nucleon' in nuclear reactions?
A) It determines the decay mode.
B) It is directly proportional to the Q-value.
C) It explains why fusion and fission release energy.
D) It is related to the cross section.
12. The probability of a neutron-induced reaction is often described by its:
A) Half-life
B) Decay constant
C) Cross section
D) Q-value
13. Which nuclear decay mode does not change the mass number of the nucleus?
A) Alpha decay
B) Beta decay
C) Gamma decay
D) Spontaneous fission
14. Photonuclear reactions are typically observed with gamma rays of energy:
A) Below 1 MeV
B) Around 10 MeV
C) In the X-ray range
D) In the radio wave spectrum
15. What is the term for a nuclear reaction where the incident particle transfers energy and momentum to the target nucleus, but does not form a compound nucleus?
A) Compound nucleus reaction
B) Direct reaction
C) Fusion reaction
D) Fission reaction
16. The Q-value of a nuclear reaction is essentially the difference in:
A) Kinetic energies of reactants and products
B) Masses of reactants and products
C) Number of protons and neutrons
D) Nuclear radii
17. Which particle is primarily responsible for initiating a chain reaction in nuclear fission?
A) Alpha particle
B) Proton
C) Neutron
D) Electron
18. Beta-plus decay decreases the atomic number of the nucleus by:
A) 1
B) 2
C) 0
D) -1
19. Beta-minus decay increases the atomic number of the nucleus by:
A) 1
B) 2
C) 0
D) -1
20. A nucleus that undergoes alpha decay will have its atomic number decreased by:
A) 0
B) 1
C) 2
D) 4
21. A nucleus that undergoes alpha decay will have its mass number decreased by:
A) 1
B) 2
C) 4
D) 8
22. What is the primary difference between nuclear fission and nuclear fusion?
A) Fission splits heavy nuclei; fusion combines light nuclei.
B) Fission releases energy; fusion absorbs energy.
C) Fission requires high temperatures; fusion occurs at room temperature.
D) Fission produces stable isotopes; fusion produces radioactive isotopes.
23. In the context of nuclear reactions, what does 'cross section' depend on?
A) Only the target nucleus
B) Only the incident particle
C) Both the target nucleus and the incident particle, as well as their energy
D) The ambient temperature
24. The term 'decay modes' refers to:
A) The rate at which a nucleus decays
B) The different ways an unstable nucleus can transform into a more stable one
C) The energy released during nuclear reactions
D) The probability of a nuclear interaction
25. Which of the following best describes the process of pair production induced by a high-energy photon?
A) A photon creates an electron-positron pair near a nucleus.
B) A photon is absorbed by a nucleus, causing fission.
C) A photon ejects a neutron from a nucleus.
D) A photon causes an electron to be emitted from the nucleus.
26. What is the phenomenon where a nucleus absorbs a gamma ray photon and becomes excited?
A) Photofission
B) Photoexcitation
C) Pair production
D) Photoproduction
27. A nuclear reaction with Q = 0 is:
A) Exothermic
B) Endothermic
C) Elastic
D) Inelastic
28. What is the term for a nuclear reaction where the incident particle is absorbed by the target nucleus, and the resulting excited nucleus immediately decays?
A) Direct reaction
B) Compound nucleus reaction
C) Resonance reaction
D) Scattering reaction
29. Which type of nuclear reaction is the primary energy source of stars like the Sun?
A) Nuclear fission
B) Nuclear fusion
C) Radioactive decay
D) Photonuclear reactions
30. In nuclear reactions, 'cross section' is a measure of:
A) Nuclear size
B) Nuclear stability
C) Reaction probability
D) Energy released
31. The Q-value calculation for a nuclear reaction relies on the principle of:
A) Conservation of momentum
B) Conservation of energy and mass defect
C) Conservation of charge
D) Conservation of angular momentum
32. Which of the following is NOT a fundamental decay mode?
A) Alpha decay
B) Beta decay
C) Gamma decay
D) Spontaneous fission
33. The energy released in nuclear fusion reactions primarily comes from:
A) The conversion of mass to energy according to E=mc²
B) The excitation of electrons
C) The release of binding energy per nucleon
D) Both A and C
34. What are the primary products of the fission of Uranium-235 by a thermal neutron?
A) Two lighter nuclei and several neutrons
B) A single heavier nucleus
C) Alpha particles and gamma rays
D) Positrons and neutrinos
35. What is electron capture?
A) A nucleus absorbing an electron from its inner shell, converting a proton to a neutron
B) A nucleus emitting an electron
C) A nucleus absorbing an electron from the surrounding environment
D) An electron combining with a proton to form a neutron
36. Which type of decay is often accompanied by gamma emission?
A) Alpha decay
B) Beta decay
C) Electron capture
D) All of the above
37. In a photonuclear reaction, a gamma ray photon can eject a particle from the nucleus. This process is called:
A) Photodisintegration
B) Photoelectric effect
C) Compton scattering
D) Pair production
38. Photonuclear reactions involve the interaction of gamma rays with:
A) Electrons
B) Protons
C) Nuclei
D) Neutrinos
39. What does the 'cross section' conceptually represent in nuclear physics?
A) The physical size of the nucleus
B) The probability of a specific nuclear interaction occurring
C) The energy released in a nuclear reaction
D) The velocity of incident particles
40. A larger cross section for a particular nuclear reaction implies:
A) A lower probability of the reaction occurring
B) A higher probability of the reaction occurring
C) The reaction is exothermic
D) The reaction is endothermic
41. What is the unit commonly used to express the cross section of a nuclear reaction?
A) Watt
B) Joule
C) Barn
D) Coulomb
42. An endothermic nuclear reaction is characterized by a Q-value that is:
A) Positive
B) Negative
C) Zero
D) Infinite
43. A nuclear reaction with a positive Q-value is:
A) Endothermic
B) Exothermic
C) Isobaric
D) Isomeric
44. What does the Q-value of a nuclear reaction represent?
A) The number of neutrons emitted
B) The energy released or absorbed in the reaction
C) The rate of decay
D) The half-life of the product nucleus
45. A nuclear reaction where a nucleus is bombarded by a particle, leading to a change in its composition, is known as:
A) Spontaneous fission
B) Radioactive decay
C) Induced nuclear reaction
D) Electron capture
46. Nuclear fusion is the process where:
A) A heavy nucleus splits into lighter nuclei
B) Light nuclei combine to form a heavier nucleus
C) A nucleus emits an alpha particle
D) A nucleus emits a beta particle
47. What is the process called when a nucleus splits into two or more smaller nuclei?
A) Fusion
B) Fission
C) Transmutation
D) Radioactive decay
48. Gamma decay primarily involves the release of energy in the form of:
A) Alpha particles
B) Beta particles
C) Neutrons
D) High-energy photons
49. In beta-plus decay, what particle is emitted along with a neutrino?
A) Electron
B) Neutron
C) Positron
D) Proton
50. What is the primary characteristic of beta-minus decay?
A) Emission of a helium nucleus
B) Emission of an electron and an antineutrino
C) Emission of a positron and a neutrino
D) Emission of a high-energy photon