Chapter 11: Nuclear Physics
TRUE/FALSE
1. The atomic number equals the number of protons in a nucleus.
2. Two isotopes have the same mass number.
3. The symbol indicating the atomic number of a nucleus is A.
4. The symbol indicating the number of protons in a nucleus is N.
5. The symbol indicating the mass number of a nucleus is A.
6. The symbol indicating the number of nucleons in a nucleus is N.
7. The symbol indicating the number of neutrons in a nucleus is N.
8. An alpha particle is another name for a helium nucleus.
9. Helium always has two neutrons in its nucleus.
10. In the case of alpha decay, the atomic number of the nucleus increases.
11. A beta particle is another name for a helium nucleus.
12. A gamma ray is another name for an electron.
13. Alpha, beta, and gamma particles are all deflected by a magnetic field.
14. When radium-223 (Z = 88) decays to radon-119 (Z = 86), an alpha particle is emitted.
15. When sulfur-35 (Z = 16) decays to chlorine-35 (Z = 17), an alpha particle is emitted.
16. When a neutron decays to a proton, a beta particle is emitted.
17. When a nucleus in an excited state decays to the ground state, a beta particle is emitted.
18. The number of protons in a nucleus equals the number of neutrons.
19. The time interval during which a nucleus has a 50% probability of decaying is its half life.
20. If one waits for a time equal to two half-lives for a certain radioactive material, all of it
originally present will have decayed completely.A
21. The half life of uranium-232 is 70 years. The time for 3/4 of a sample of uranium-232 to
decay is 105 years.
22. A Geiger counter registers a count rate of 8,000 counts per minute from a sample of a
radioisotope. The count rate 24 minutes later is 1,000 counts per minute. The half life of the
radioisotope is 8 minutes.
23. The Voyager space probes used electricity provided by solar arrays.
24. Fusion of hydrogen nuclei is the origin of solar energy.
25. Fusion is used to produce the largest nuclei known to exist.
26. Fission fragments are always identical.
27. Carbon-14 dating can be used to find the age of material up to millions of years old.
28. The hydrogen in the universe was formed by the energy of the Big Bang.
29. The half life indicates how tightly the nucleons in a nucleus are bound together.
30. The splitting of a large nucleus into two smaller nuclei upon absorbing a neutron is nuclear
fusion.
31. The combining of two nuclei to form a larger nucleus with the release of energy is nuclear
fusion.
32. Atomic bombs and nuclear power plants both use nuclear fusion.
33. Both nuclear reactors and atomic bombs use nuclear chain reactions.
34. Nuclear fusion is the source of energy in stars.
35. The average mass of each neutron in the nucleus of an iron atom is not the same as the
average mass of each neutron in the nucleus of a gold atom.
36. The determination of the composition of a material by bombarding it with neutrons and
monitoring the emitted radiation is neutron activation analysis.
37. Gamma radiation is used to kill harmful bacteria in food.
38. The product of a radioactive decay is called the “daughter.”
39. When uranium-238 (Z = 92) is bombarded with a neutron, it can change into uranium-237.
40. The mass of an atom of carbon-12 (Z = 6) is less than the mass of 6 protons and 6 neutrons
because of binding energy.
41. Magnetic confinement is used in controlled fusion experiments to control a plasma.
42. A nuclear reactor could explode like an atomic bomb.
43. The energy of nuclear radiation as it is absorbed mostly goes to heat the material.
44. After three half-lives, 3/4 of the nuclei in a sample of a radioisotope have decayed
45. Einstein’s equation E = mc2 states that when a particle loses energy, the result is an increase
in mass of the particle.
46. An alpha particle is like with 2 protons and 2 neutrons, whereas a beta particle is
equivalent to hydrogen.
MULTIPLE CHOICE
1. What’s an isotope?
a.
a radioactive material
b.
an atom of an element with a different number of neutrons in the nucleus
c.
an electrically charged atom
d.
none of the above
2. The number of protons in a nucleus is the
a.
mass number
b.
neutron number
c.
atomic number
d.
isotope number
e.
none of the above
3. Two isotopes have the same
a.
mass number
b.
neutron number
c.
atomic number
d.
quantum number
e.
none of the above
4. How big is the nucleus of an atom?
a.
about 1% of the volume of the whole atom
b.
about a millionth of the volume of the whole atom
c.
about a billionth of the volume of the whole atom
d.
about a trillionth of the volume of the whole atom
5. What holds the nucleus together?
a.
electrical forces between the protons
b.
alpha particles
c.
beta particles
d.
strong forces
6. The expression(s) indicating the atomic number of a nucleus is
a.
A
b.
N
c.
Z
d.
Z + N
e.
A – Z
7. The expression(s) indicating the number of protons in a nucleus is
a.
A
b.
N
c.
Z
d.
Z + N
e.
A – Z
8. What does the 235 represent in uranium-235?
a.
the mass number
c.
the neutron number
b.
the atomic number
d.
none of the above
9. If someone tells you they have a sample of niobium-90, can you tell how many neutrons are
in the nucleus?
a.
Yes, there are 41 neutrons.
b.
Yes, there are 90 neutrons.
c.
Yes, there are 49 neutrons.
d.
No, more information must be given.
e.
No, there is no such thing as “niobium.”
10. What is ?
a.
There is no such thing.
b.
an isotope of carbon with 7 neutrons and 12 protons
c.
an isotope of carbon with 7 neutrons and 5 protons
d.
an isotope of carbon with 5 neutrons and 7 protons
11. An alpha particle is another name for a(n)
a.
electron
b.
proton
c.
neutron
d.
helium nucleus
e.
photon
12. A beta particle is another name for a(n)
a.
electron
b.
proton
c.
neutron
d.
helium nucleus
e.
photon
13. How can an electron be ejected from a nucleus in beta decay if it wasn’t in the nucleus to
begin with?
a.
The electron doesn’t come from the nucleus—it comes from an orbit circling the
nucleus.
b.
A neutron in the nucleus turns into a proton, electron, and a neutrino.
c.
A proton in the nucleus turns into a neutron, electron, and a neutrino.
d.
none of the above
14. A gamma ray is another name for a(n)
a.
electron
b.
proton
c.
neutron
d.
helium nucleus
e.
photon
15. If a substance is radioactive it is definitely
a.
dangerous
b.
emitting alpha particles
c.
glowing
d.
useful
e.
all of the above
f.
none of the above
16. Low levels of ionizing radiation
a.
are dangerous to the human body
b.
can be tolerated by the human body
c.
are beneficial to the human body
d.
none of the above
17. Why is nuclear reactor waste radioactive?
a.
Radiation from the reactor makes everything in or near it radioactive.
b.
Used fuel rods contain fission fragments which are radioactive.
c.
Spent fuel rods pick up contamination from the reactor.
d.
all of the above
18. What does the moderator do in a nuclear reactor?
a.
It is a safety feature that limits the nuclear reaction.
b.
It absorbs neutrons.
c.
It slows down neutrons.
d.
none of the above
19. Why is there a radioactive source in a smoke detector?
a.
It makes the smoke particles radioactive.
b.
It ionizes the air.
c.
It powers the alarm when the battery wears out.
d.
none of the above
20. When radium-223 (Z = 88) decays to radon-119 (Z = 86), the other particle emitted is a(n)
a.
alpha particle
b.
beta particle
c.
gamma ray
d.
x ray
e.
none of the above
21. When sulfur-35 (Z = 16) decays to chlorine-35 (Z = 17), a particle emitted is a(n)
a.
alpha particle
b.
beta particle
c.
gamma ray
d.
x ray
e.
none of the above
22. What’s a decay chain?
a.
a nuclear chain reaction
b.
one radioisotope decaying into another, which decays into another, and so on
c.
the triggering of multiple fissions by a single neutron
d.
none of the above
23. When a neutron decays to create a proton, another particle emitted is a(n)
a.
alpha particle
b.
beta particle
c.
gamma ray
d.
x ray
e.
none of the above
24. When a nucleus in an excited state decays to the ground state, the particle emitted is a(n)
a.
alpha particle
b.
beta particle
c.
gamma ray
d.
x ray
e.
none of the above
25. The time interval during which a nucleus has a 50% probability of decaying is its
a.
half life
b.
decay time
c.
nuclei activation time
d.
binding energy time
e.
none of the above
26. The half life of uranium-232 is 70 years. The time for 3/4 of a sample of uranium-232 to
decay is
a.
35 years
b.
70 years
c.
125 years
d.
140 years
e.
none of the above
27. A Geiger counter registers a count rate of 8,000 counts per minute from a sample of a
radioisotope. The count rate 24 minutes later is 1,000 counts per minute. The half life of the
radioisotope is
a.
3 minutes
b.
4 minutes
c.
6 minutes
d.
8 minutes
e.
12 minutes
28. The Voyager space probes used electricity provided by
a.
fuel cells
b.
solar arrays
c.
radioisotope thermoelectric generators
d.
hydrazine
e.
none of the above
29. Carbon-14 dating can be used to find the age of material up to ____________ of years old.
a.
millions
hundreds of thousands
b.
billions
tens of thousands
30. The hydrogen in the universe was formed by
a.
the energy of the Big Bang
b.
nuclear fusion reactions in stars
c.
radioactive decay of heavy elements
d.
none of the above
31. Which of the following is not a method of producing nuclear fusion?
a.
heating a magnetically confined plasma
b.
forcing nuclei together using lasers
c.
cooling nuclei to very cold temperatures
d.
forcing nuclei together with a nuclear fission explosion
32. What do you do to the control rods of a reactor in order to shut it down?
a.
push them into the core
b.
pull them out of the core
c.
nothing—it’s the cooling water that shuts down the reactor
d.
none of the above
33. How tightly the nucleons in a nucleus are bound together is indicated by the nucleus’s
a.
atomic number
b.
mass number
c.
neutron number
d.
half life
e.
binding energy
34. The splitting of a large nucleus into two smaller nuclei upon absorbing a neutron is
a.
nuclear fission
b.
nuclear fusion
c.
neutron activation
d.
nuclear emission
e.
beta decay
35. The combining of two nuclei to form a larger nucleus with the release of energy is
a.
nuclear fission
b.
nuclear fusion
c.
neutron activation
d.
nuclear emission
e.
beta decay
36. Which of the following is not the usual outcome of nuclear fission?
a.
The binding energy per nucleon of the fission fragments is smaller than that of the
original nucleus.
b.
Energy is released.
c.
Neutrons are released.
d.
The fission fragments are radioactive.
37. What do “kiloton” and “megaton” refer to?
a.
explosive yields of nuclear weapons
b.
kiloton means 1000 tons of TNT
c.
megaton means one million tons of TNT
d.
all of the above
38. The determination of the composition of a material by bombarding it with neutrons and
monitoring the emitted radiation is
a.
nuclear fission analysis
b.
nuclear fusion analysis
c.
neutron activation analysis
d.
nuclear emission analysis
e.
beta decay analysis
39. When uranium-238 (Z = 92) is bombarded with a neutron, it can change into
a.
uranium-237
b.
uranium-239
c.
protactinium-239 (Z = 91)
d.
neptunium-239 (Z = 93)
e.
none of the above
40. The mass of an atom of carbon-12 (Z = 6) is less than the mass of 6 protons and 6 neutrons
because of
a.
nuclear fission
b.
nuclear fusion
c.
neutron activation
d.
nuclear emission