Chapter 30 (Nuclear Physics)
1. A plasma can be contained in a “magnetic bottle” because it has which of the following properties?
a. high temperature
b. liquid in form
c. made of charged particles
d. made of light elements
2. The advantage of a fusion reactor when compared to a fission reactor is which of the following?
a. the fuel is cheaper
b. there is less radioactive waste material
c. both choices above are valid
d. none of the above choices are valid
3. If a self‑sustained controlled fusion reaction is to operate, a condition which must be met is that the fuel material be subjected to which of the following condition(s)?
a. confined for sufficient time period
b. have sufficiently high density
c. be at sufficiently high temperature
d. all of the above choices are valid
4. The mass of a proton is greater if it is in the nucleus of which of the following elements?
a. hydrogen
b. iron
c. uranium
d. krypton
5. It is possible to detect small amounts of arsenic in the hair of a deceased person by a technique involving which of the following?
a. Carbon‑14 dating
b. nuclear fission
c. neutron activation
d. isotopic separation
6. When comparing product nuclei to reactant nuclei in an exothermal nuclear fusion process, which has the greater binding energy per nucleon?
a. greater in product nuclei
b. greater in reactant nuclei
c. equal in both product and reactant nuclei
d. none of the above choices are valid
7. A capture by a target nucleus of uranium‑235 is most apt to occur for which type of “bullet” particle?
a. low velocity alpha particle
b. low velocity proton
c. high velocity neutron
d. low velocity neutron
8. In order to be useful in sustaining a reaction, the neutrons in a fission reactor must be:
a. released from the reactor
b. warmed to a higher temperature
c. accelerated
d. decelerated
9. In a nuclear reactor which uses the fission process, which of the following is the most likely result in the event of a cooling system failure followed by a nuclear accident?
a. proliferation of plutonium fuel
b. accumulation of critical mass of fissionable material
c. spread of radioactive material into the environment
d. reduction of ozone in upper atmosphere
10. In a nuclear fusion reactor, the Lawson criterion prescribes the necessary conditions, as related to density and confinement time of the plasma fuel, in order that the process produces a net power output. If the fuel density were doubled, by what factor would the required confinement time change?
a. 0.25
b. 0.50
c. 1.4
d. 2.0
11. Assume that (i) the energy released per fission event of U‑235 is 208 MeV and (ii) 30% of the nuclear energy released in a power plant is ultimately converted to usable electrical energy. Approximately how many fission events will occur in one second in order to provide the 2.0 kW electrical power needs of a typical home? (1 eV = 1.6 ´ 10‑19 J)
a. 3 ´ 1010 fissions per sec
b. 2 ´ 1014 fissions per sea
c. 5 ´ 1018 fissions per sea
d. 3 ´ 1021 fissions per sea
12. Calculate the energy released in the following fusion reaction where reactants are Li‑6 and a neutron; products are He‑4 and H‑3. (atomic masses: Li‑6, 6.01512; neutron, 1.00867; He‑4, 4.00260; H‑3, 3.016031; also 1 u ´ c2 = 931.5 MeV)
a. 2.9 MeV
b. 4.8 MeV
c. 8.6 MeV
d. 17.2 MeV
13. What characteristic is preferred in the elements contained in moderator materials when used in a nuclear fission reactor?
a. low atomic mass
b. metallic
c. non‑metallic
d. high atomic mass
14. The water surrounding the fuel rods in a nuclear fission reactor serves what purpose(s)?
a. coolant
b. moderator
c. both choices above are valid
d. none of the choices above are valid
15. The K‑ratio in a uranium fuel reactor is defined as the average number of neutrons from each fission event that will cause another event. In a well‑functioning reactor, it is desired that the K‑ratio have what value?
a. zero
b. 0.5
c. 1.0
d. 2.0
16. In a fusion reactor, the high temperature of the order of 108 K is required in order that what condition is met?
a. melt down the hydrogen fuel
b. strip the hydrogen atoms of their electrons
c. break the protons into their elementary particle sub‑parts
d. overcome Coulomb repelling forces between protons
17. In a fission reaction, a U‑235 nucleus captures a neutron. This results in the creation of the products Ba-141 and Kr-92 along with how many neutrons?
a. 1
b. 2
c. 3
d. 5
18. In a fission reaction, a U‑235 nucleus captures a neutron. What energy is released if the products are I‑139, Y‑95 and two neutrons? (atomic masses: U‑235, 235.0439: I‑139, 138.9350; Y‑95, 94.9134; neutron, 1.00867; and 1 u ´ c2 = 931.5 MeV)
a. 123 MeV
b. 174 MeV
c. 199 MeV
d. 218 MeV
19. In a nuclear fission process involving the use of Pu‑239 fuel, if the approximate average binding energy per nucleon in the product fragments is 8.5 MeV while that of the fuel atom is 7.7 MeV, what approximate net energy is released per fission?
a. 191 MeV
b. 239 MeV
c. 2030 MeV
d. 3850 MeV
20. The rate that an organism absorbs and circulates nutrient materials into its body can be measured by a nuclear technique involving which of the following?
a. neutron activation
b. tracing
c. scintillation counting
d. plasma confinement
21. Which of the following will not influence the rate at which nuclear reactions will occur in a nuclear power plant where the fuel elements are a mixture of U‑235 and U‑238?
a. The presence of moderating material
b. The presence of control rods
c. The percentage of U‑235 relative to U‑238
d. The percentage of the energy that is used to produce electricity
22. Which of the following can only occur if the reproduction constant, K, exceeds 1?
a. Nuclear meltdown at a nuclear power plant
b. Explosive release of radioactivity and steam from a nuclear power plant
c. The explosion of a nuclear bomb
d. All of the above require that K exceed 1
23. One result of thermal pollution in water near nuclear power plants in Canada is that:
a. roses can be grown near the plant in December.
b. the water contains toxic poisons.
c. the fish in the water are radioactive.
d. all the fish in the water are killed.
24. The formation of a star requires the consideration of the effects of gravity and the energy from nuclear reactions and a star will form only when both the temperature and density are sufficiently high. In the birth of a star:
a. gravity produces the initial required high temperature and density.
b. nuclear reactions produce the initial high temperature.
c. nuclear reactions produce the initial required high density.
d. nuclear reactions produce the initial required high temperature and density.
25. The reason that a thermonuclear fusion reaction cannot be maintained in the oceans of the earth is because:
a. the temperature is not high enough.
b. the density is not high enough.
c. there is insufficient deuterium in the ocean.
d. the deuterium in the ocean is not radioactive.
26. The plasma in a fusion reactor is confined in a magnetic bottle because otherwise:
a. the plasma would become cooler if it touched a container
b. the plasma would melt the walls of any regular container.
c. the container would become radioactive.
d. the container would not be strong enough to contain the plasma.
27. One in 6500 water molecules contains a deuterium atom. If all the deuterium could be extracted from 1 m3 of water and then reacted, how much energy could be obtained? (Each D‑D fusion liberates 3.65 MeV of energy, 1 MeV = 1.6 ´ 10‑13 J)
a. 8.0 ´ 1010 J
b. 9.6 ´ 1010 J
c. 4.8 ´ 1011 J
d. 1.5 ´ 1012 J
28. How much kinetic energy must a deuterium ion (charge = 1.6 ´ 10‑19 C) have to approach within 10‑14 m of another deuterium ion? [k = 9 ´ 109 N‑m2/C2 and 1 MeV = 1. 6 ´ 10‑13 J]
a. 30 keV
b. 50 keV
c. 70 keV
d. 140 keV
29. How fast is an ion of deuterium moving if it is in a plasma with a temperature of 108 K? (kB = 1.38 ´ 10‑23 J/K and mD = 2 ´ 1.66 ´ 10-27 kg)
a. 1.12 ´ 106 m/s
b. 0.93 ´ 105 m/s
c. 0.46 ´ 105 m/s
d. 2.32 ´ 104 m/s
30. Calculate the energy (in kWh) given off if 1 kg of plutonium‑239 undergoes complete fission. The energy released per fission is 200 MeV. (1 MeV = 1.6 ´ 10‑13 J)
a. 1.17 ´ 105 kWh
b. 7.67 ´ 106 kWh
c. 11.4 ´ 106 kWh
d. 22.3 ´ 106 kWh
31. Which particle was the last to be discovered?
a. electron
b. neutrino
c. neutron
d. proton
32. Which particle in the free state is least stable?
a. electron
b. neutrino
c. neutron
d. proton
33. Which of the following forces is the weakest?
a. strong nuclear
b. weak nuclear
c. electromagnetic
d. gravitational
34. Which force can act over distances comparable to the distance between planets?
a. only gravitational
b. only electrical
c. only magnetic
d. all of the above
35. The Dirac theory predicted that a positron would be:
a. a negative electron in a negative energy state.
b. a particle with same mass as an electron but with opposite charge and spin.
c. a particle with negative mass.
d. all of the above
36. A positron and an electron differ in:
a. charge.
b. mass.
c. spin.
d. energy.
37. The size and sign of the charge on an electron is the same as that for:
a. a positron.
b. an anti‑proton.
c. an anti‑neutron.
d. an anti‑neutrino.
38. Which of these particles has the most mass?
a. pion.
b. muon.
c. electron.
d. positron.
39. Calculate the range of the force that might be produced by the virtual exchange of a proton. (mp = 1.67 ´ 10‑27 kg, c = 3 ´ 108 m/s, and h/2π = 1.05 ´ 10-34 J‑s)
a. 6.7 ´ 10‑25 m
b. 2.0 ´ 10‑16 m
c. 6.0 ´ 10‑8 m
d. 1.5 ´ 10‑15 m
40. The virtual exchange of photons can produce:
a. a repulsive force.
b. an attractive force.
c. either a repulsive or an attractive force.
d. neither a repulsive nor an attractive force.
41. Which of the following particles has not been observed experimentally?
a. photon
b. graviton
c. gluon
d. Z˚ boson
42. According to present theories, there is a neutrino for all the following particles except:
a. neutral pion.
b. electron.
c. muon.
d. tau lepton.
43. A neutron and a proton have the same:
a. charge.
b. spin.
c. mass.
d. baryon number.
44.
What quantity is conserved in the following reaction?
a. baryon number
b. charge
c. lepton number
d. all of the above
45.
What quantity is conserved in the following reaction?
a. baryon number
b. charge
c. lepton number
d. all of the above
46. A photon hits an electron and an anti‑proton is created. Some uncharged particles must have left the collision. These are:
a. neutron and neutrino.
b. neutron and anti‑neutrino.
c. photon and neutrino.
d. photon and anti‑neutrino.
47. A negative muon decays to form an electron and a neutrino and one additional particle. The other particle must be a(n):
a. positron.
b. anti‑neutrino.
c. neutrino.
d. photon.
48. If a negative muon decays to form an electron‑positron pair and one other particle, the other particle may be a(n):
a. positron.
b. anti‑neutrino.
c. neutrino.
d. electron.
49. If a photon produces an electron‑positron pair and one other particle, the other particle may be a(n):
a. muon.
b. anti‑neutrino.
c. neutrino.
d. photon.
50. Experimentally, strange particles can be produced in abundance but they decay relatively slowly. This occurs because strangeness:
a. is conserved in both their production and decay.
b. is conserved in their production but not in their decay.
c. is conserved in their decay but not in their production.
d. is not conserved in either their production or their decay.
51. The strangeness of an anti‑proton is:
a. +1
b. 0
c. ‑1
d. ‑2
52. The S+, S0, and S– all have strangeness of (‑1). The collision of a proton and a neutron to produce a S0 and an anti‑S– cannot occur because it does not conserve:
a. strangeness.
b. charge.
c. baryon number.
d. all of the above
53. The S+, S0, and S– all have strangeness of (‑1). The collision of an anti‑proton and a neutron may produce which of the following particles?
a. S– and S0
b. S+ and anti‑S0
c. anti‑S+ and S0
d. anti‑S– and S0
54. According to the standard model, a quark and its antiquark may have the same:
a. spin.
b. baryon number.
c. color.
d. all of the above may be the same
55. According to the standard model, there are some cases in which a quark and its anti‑quark have the same:
a. charge.
b. baryon number.
c. strangeness.
d. all of the above are always different
56. If two quarks in an anti‑proton have the color anti‑red and anti‑blue, the third quark must have the color:
a. red.
b. blue.
c. anti‑purple.
d. anti‑green.
57. The spin of all quarks is:
a. 0.
b. 1/2.
c. 1.
d. 1/3 or 2/3.
58. The charge of some quarks or anti‑quarks is:
a. 0.
b. 1/2 (1.6 ´ 10‑19) C.
c. 1/3 (1.6 ´ 10‑19) C.
d. 1 (1.6 ´ 10‑19) C.
59. The strong force that acts between an electron and a quark is caused by the exchange of:
a. photons.
b. gluons.
c. gravitons.
d. W+, W–, and Z0 bosons.
60. Theoretical physicists have had the least success in combining which force with the electromagnetic force?
a. strong nuclear force
b. weak nuclear force
c. gravitational force
d. electrical Coulomb force
61. Theoretical physicists have had the greatest success in combining which force with the electromagnetic force?
a. strong nuclear force
b. weak nuclear force
c. gravitational force
d. the force caused by the exchange of gluons
62. The pion (mπ = 135 MeV/c2) is thought to be the particle exchanged in the nuclear force. What is the maximum range of this particle if its “time of existence” is as long as can be allowed by the uncertainty principle? (h = 1.054 ´ 10‑34 J‑S)
a. 1.2 ´ 10‑15 m
b. 1.5 ´ 10‑15 m
c. 2.0 ´ 10‑15 m
d. 7.5 ´ 10‑15 m
63.
The attractive force between protons and neutrons in the nucleus is
brought about by the exchange of a virtual pi‑meson (mπ
= 140 MeV/c2). Estimate the longest time a π˚ can exist in
accordance with the uncertainty principle
a. 3.3 ´ 10‑18 s
b. 2.4 ´ 10‑21 s
c. 4.7 ´ 10‑24 s
d. 6.9 ´ 10‑27 s
64. Which of the following particle reactions cannot occur?
65. Which of the following particle reactions cannot occur?
66. Which of the following is not true of neutrinos?
a. spinless
b. chargeless
c. massless
d. lepton
67. Which of the following decays violates conservation of lepton number?
68. A proton and antiproton each with total energy 400 GeV collide head‑on. What is the total energy (particles + energy) released?
a. 800 GeV
b. 400 GeV
c. zero
d. 1600 GeV
69.
The following reaction can occur by the strong interaction: π˚ + n
® K+ +
S–. If the quark
composition of the n is (udd), the πo is
and
the composition of the K+ is
,
find the quark composition of the S–.
a. dds
b. uds
c. sss
d.
70. If a K˚ meson at rest decays in 0.9 ´ 10-10 s, how far will a K˚ meson moving at 0.96 c travel through a bubble chamber?
a. 9.3 cm
b. 1.1 cm
c. 53 cm
d. 42 cm
Notes:
Chapter 30 - Answers
# Ans Difficulty # Ans Difficulty
1. C 1 36. A 2
2. C 1 37. B 1
3. D 1 38. A 2
4. A 1 39. B 2
5. C 2 40. C 1
6. A 1 41. B 1
7. D 1 42. A 1
8. D 1 43. D 1
9. C 1 44. D 1
10. B 1 45. B 2
11. B 2 46. A 2
12. B 2 47. B 2
13. A 1 48. D 2
14. C 1 49. D 2
15. C 1 50. B 2
16. D 1 51. B 1
17. C 1 52. C 2
18. B 2 53. C 2
19. A 2 54. A 3
20. B 1 55. C 3
21. D 1 56. D 3
22. C 1 57. B 2
23. A 1 58. C 1
24. A 1 59. A 2
25. A 1 60. C 1
26. A 1 61. B 1
27. D 2 62. B 3
28. D 2 63. C 3
29. A 3 64. A 2
30. D 2 65. B 2
31. B 1 66. A 1
32. C 1 67. D 2
33. D 1 68. A 1
34. D 1 69. A 2
35. B 2 70. A 3