{image} {image} {image} {image} {image}

1. 1. 2. 3. 4. 5. Outside the nucleus, the beta decay {image} will not occur because the neutron and electron have more total mass than the proton. This process can occur within the nucleus, if we consider the mass-energy changes of the entire nuclear system, not just the individual particles. What is a reasonable mean lifetime for free protons? • {image} • {image} • {image} • {image} • {image}

2. 1. 2. 3. 4. 5. Find the unknown atomic number and mass number respectively, for the following reaction: {image} • 56, 140 • 56, 141 • 141, 56 • 140, 57 • 55, 120

3. 1. 2. 3. 4. 5. Find the number of nuclei per unit volume {image} for europium. {image} {image} {image} • {image} • {image} • {image} • {image} • {image}

4. The nuclear scattering cross-sections of neutrons depend most strongly on the neutron's _____. • volume • area • charge • mass • speed

5. 1. 2. 3. 4. 5. What energy does a thermal neutron have? • {image} • {image} • {image} • {image} • {image}

6. 1. 2. 3. 4. 5. A neutron is characterized by the term "cold neutron" when _____. • its energy is of the order {image} where {image} is on the order of {image} • its energy is of the order {image} where {image} is on the order of {image} • its energy is of the order {image} where {image} is on the order of {image} • its energy is of the order {image} where {image} is on the order of {image} • its energy is of the order {image} where {image} is on the order of {image}

7. How much energy (in MeV) is released when a {image} fissions to {image} and {image} in the reaction {image} {image} {image} {image} {image} {image} • 230 • 210 • 60 • 250 • 160

8. Approximately how much uranium (in kg) must undergo fission per day to provide 2,200 MW of power? (Assume an efficiency of 29%). The nuclear reaction is {image} {image} {image} {image} {image} {image} • 3.4 • 7.9 • 5.3 • 0.3 • 1.9

9. What is the average kinetic energy (in keV) of an ion that has a temperature of {image} • 19 • 26 • 30 • 9 • 3

10. A self-sustained chain reaction occurs when the reproduction constant, {image} is equal to _____. • 3.0 • 2.5 • 1.0 • 5.0 • 0.9

11. 1. 2. 3. 4. 5. Approximately how fast is an ion of helium moving if it is in a plasma with a temperature of {image} {image} and {image} • {image} • {image} • {image} • {image} • {image}

12. What energy is needed (in keV) so two deuterium atoms moving together will reach {image} ? • 200 • 1,300 • 21 • 30 • 36

13. 1. 2. 3. 4. 5. How fast must two deuterium atoms be moving so they can overcome the Coulomb force of repulsion, and attain {image} ? {image} • {image} • {image} • {image} • {image} • {image}

14. 1. 2. 3. 4. 5. A principal mechanism for energy loss during nuclear fusion is bremsstrahlung. What is this loss associated with? • radiation losses due to {image} losses • x-rays emitted due to electron-ion collisions • diminution of ion density {image} • conduction losses associated with {image} • neutron collisions with atoms of moderator

15. 1. 2. 3. 4. 5. How can one roentgen be defined? • the amount of ionizing radiation that will produce {image} of electric charge in {image} of air under standard conditions • the amount of radiation needed for fusion process • the amount of of emitted radiation when an atom makes a transition from the excited to the ground energy state • the amount of radiation that deposits 1 erg of energy in 1 g of air • the number of rads of x-radiation or gamma radiation that produces the same biological damage as 1 rad of the radiation being used

16. Calculate the thickness (in mm) of lead which reduces the intensity of a beam of x-rays whose wavelength is 60 pm by a factor of five. (The linear absorption coefficient of lead is {image} for x-rays of wavelength {image} • 0.30 • 7.3 • 8.9 • 0.33 • 0.37

17. How can a rem (roentgen equivalent in man) be defined? • the product of the dose in roentgen and the RBE factor • the quotient of the dose in rad by energy of radiation • the product of the dose in rad and the RBE factor • the dose in rad times the dose in roentgen • the dose in RBE

18. Which of the following is not a radiation detector? • spark chamber • cloud chamber • control rod • proportional counter • semiconductor-diode detector

19. What is the most likely result when a fast neutron collides with a hydrogen or deuterium nucleus? • The neutron has an appreciable loss in kinetic energy, the loss being greatest for head-on collisions. • The neutron has an appreciable gain in kinetic energy, the gain being greatest for oblique collisions. • The neutron is absorbed by the hydrogen or deuterium nucleus. • The neutron has an appreciable gain in kinetic energy, the gain being greatest for head-on collisions. • The neutron has an appreciable loss in kinetic energy, the loss being greatest for oblique collisions.

20. 1. 2. 3. 4. 5. In order to control a nuclear reactor, control rods can be pulled out of or pushed into the reactor core by remote control. These rods control the reactor by _____. • speeding up slow neutrons so the neutrons can be absorbed by {image} • slowing down fast neutrons so they cannot initiate further fusion reactions in {image} • capturing thermal neutrons so they cannot initiate further fission reactions in {image} • speeding up fast neutrons so they cannot initiate further fusion reactions in {image} • slowing down the fast neutrons so the neutrons can be absorbed by {image}

21. 1. 2. 3. 4. 5. Radiant energy reaching the Earth from the sun is not sufficient to keep the Earth's surface temperature comfortable for life. What is the most likely source of the additional thermal energy? • Fission of radioactive nuclei inside the Earth. • Fusion of hydrogen nuclei in the Earth's core. • Nuclear reactors. • Fusion of high {image} nuclei in the Earth's core. • Fission of radioactive nuclei in cosmic rays.

22. Background radiation from cosmic rays and radioactive nuclei in our surroundings is about 0.13 rem/year. Suppose we assume this all comes from cosmic rays which have an RBE factor of 1.0. The RBE factor for the dangerous types of radiation is 13. How many rads of the dangerous radiation could a 50-year-old person have been exposed to in her lifetime without having gone over the recommended limit of 0.5 rem/year? • 4.7 • 38 • 0.68 • 1.4 • 2.33

23. Radioactive technetium, a gamma emitter, is taken up by the heart muscle in a medical test. What could be the detector for the radiation emitted from the heart? • medical fiberscope • photoelectric tube • gyroscope camera • proportional counter • polaroid filter

24. What type is the reaction {image} ? • photon capture • positron capture • alpha capture • electron capture • neutron emission

25. 2. 1. 3. 4. 5. When a nucleus at rest spontaneously splits into fragments of mass {image} and {image} what is the ratio of the velocity of {image} to the velocity of {image} • {image} • {image} • {image} • {image} • {image}

26. 1. 2. 3. 4. 5. When a nucleus at rest spontaneously splits into fragments of mass {image} and {image} what is the ratio of the momentum of {image} to the momentum of {image} • {image} • {image} • {image} • {image} • {image}

27. 1. 2. 3. 4. 5. What power output does a radioactive sample with decay rate {image} and decay energy {image} have? • {image} • {image} • {image} • Equal to any of the above • Equal to first and second above

28. 1. 2. 3. 4. 5. When a beam of nuclear radiation of initial intensity {image} passes through a thickness {image} of material, what is the intensity {image} of the beam exiting the material? • {image} • {image} • {image} • {image} • {image}

29. 1. 2. 3. 4. 5. A beam of 2-MeV gamma rays incident on a piece of {image} thick lead is reduced by 62% of its initial value. How thick must the lead be to reduce the beam to 2% of its initial value? • 3.5 cm • 4.1 cm • 1.0 cm • 1.8 cm • 3.8 cm

30. 1. 2. 3. 4. Which of the following is a possible set of products for a {image} fission reaction in which two neutrons are released? • {image} • {image} • {image} • {image}

31. 1. 2. 3. When a nucleus undergoes fission, the two daughter nuclei are generally radioactive. By which process are they most likely to decay? • Alpha decay. • Beta decay {image} • Beta decay {image}

32. 1. 2. 3. Which of the following are possible fission reactions? • {image} • {image} • {image}

33. Which of the following has the function of slowing down fast neutrons? • Control rods. • Moderator. • Fuel elements.

34. To reduce the value of the reproduction constant {image} you should _____. • push the control rods deeper into the core • pull the control rods farther out of the core

35. In the core of a star, hydrogen nuclei combine in fusion reactions. Once the hydrogen has been exhausted, fusion of helium nuclei can occur. Once the helium is used up, if the star is sufficiently massive, fusion of heavier and heavier nuclei can occur. Consider fusion reactions involving two nuclei with the same value of A. For these types of reactions, which of the following values of A are impossible? • 12 • 20 • 28 • 64

36. 1. 2. 3. 4. 5. List the nuclear reactions required to produce {image} from {image} under fast neutron bombardment. • {image} {image} • {image} {image} • {image} {image} • {image} {image} • {image} {image}