Matching (Value 5)
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Match each item with the correct statement below. a. | fission | e. | scintillation counter | b. | fusion | f. | neutron absorption | c. | Geiger counter | g. | neutron moderation | d. | radioisotope |
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1.
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element with unstable nucleus
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2.
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combination of two nuclei to form a nucleus of greater mass
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3.
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process that decreases the number of slow-moving neutrons
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4.
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splitting of nucleus into smaller fragments
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5.
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process that slows down neutrons so a reactor fuel can capture them to continue
a chain reaction
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6.
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radiation detector that makes use of a phosphor-coated surface
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Multiple Choice (Value 20)
Identify the choice that best completes the statement or answers
the question.
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7.
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The charge on a gamma ray is ____.
a. | +2 | c. | 0 | b. |  1 | d. |  2 |
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8.
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What is the change in atomic mass when an atom emits gamma radiation?
a. | decreases by 2 | c. | remains the same | b. | decreases by 1 | d. | increases by 1 |
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9.
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Ionizing radiation that consists of helium nuclei is ____.
a. | X radiation | c. | beta radiation | b. | gamma radiation | d. | alpha radiation |
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10.
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What is the change in atomic number when an atom emits a beta particle?
a. | decreases by 2 | c. | increases by 2 | b. | decreases by 1 | d. | increases by 1 |
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11.
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Which symbol is used for an alpha particle?
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12.
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What symbol is used for beta radiation?
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13.
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A neutron breaks down to form _____.
a. | an alpha particle | c. | a proton and an electron | b. | two
protons | d. | a helium
nucleus |
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14.
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Which type of ionizing radiation can be blocked by clothing?
a. | beta radiation | c. | gamma radiation | b. | X radiation | d. | alpha radiation |
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15.
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When radium-226 (atomic number 88) decays by emitting an alpha particle, it
becomes ____.
a. | polonium-222 | c. | radium-222 | b. | polonium-224 | d. | radon-222 |
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16.
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What particle does argon-39 (atomic number 18) emit when it decays to
potassium-39 (atomic number 19)?
a. | neutron | c. | proton | b. | electron | d. | alpha particle |
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17.
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To what element does polonium-208 (atomic number 84) decay when it emits an
alpha particle?
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18.
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Which of the following naturally occurring radioisotopes would be most useful in
dating objects thought to be millions of years old?
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19.
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Controlled nuclear chain reactions ____.
a. | take place in nuclear reactors | b. | are always fusion reactions | c. | never produce
radioactive by-products | d. | are characteristic of atomic
bombs |
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20.
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What does neutron absorption accomplish in a nuclear reactor?
a. | It slows down the reaction. | b. | It speeds up the reaction. | c. | It increases the
rate of heat absorption. | d. | It recycles the
fuel. |
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21.
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What type of radiation is best detected by a scintillation counter?
a. | alpha radiation only | c. | alpha and beta radiation only | b. | gamma radiation
only | d. | all types of
radiation |
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22.
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What is the main detector of a Geiger counter?
a. | ionizable gas in a metal tube | c. | plates of ionizable
plastic | b. | phosphor-covered surface | d. | potassium metal surface |
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23.
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What is the main detector of a scintillation counter?
a. | ionizable gas in a metal tube | c. | plates of ionizable
plastic | b. | phosphor-covered surface | d. | potassium metal surface |
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24.
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Radiation therapy is used to ____.
a. | study reaction mechanisms | c. | treat cancer | b. | detect
elements | d. | initiate neutron
activation analysis |
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25.
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Radioisotopes taken internally for medical reasons ____.
a. | must be eliminated from the body slowly | b. | should be
fissionable isotopes | c. | are usually deposited in fat
tissue | d. | should have a short half-life |
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Short Answer (Value 8)
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26.
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Complete the following nuclear reaction:  U   He +  Th
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27.
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If the half-life of a radioactive material is 8 years, how many years will it
take for one half of the original amount of material to decay?
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28.
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After 42 days, 2 g of phosphorus-32 has decayed to 0.25 g. What is the half-life
of phosphorus-32?
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29.
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The concentration of carbon-14 in a piece of wood from an ancient burial mound
indicates that two half-lives of this radioisotope have passed. If the half-life (t  ) for carbon-14 is 5730 years, approximately how many years ago did this sample of
wood die?
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Numeric Response (Value 4)
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30.
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How many neutrons are in an alpha particle?
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31.
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The half-life of radon-222 is about four days. After how many days is the amount
of radon-222 equal to one-sixteenth of its original amount?
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