Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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1.
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Which
symbol represents a positron?
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2.
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Which
of the following reactions is an example of positron emission?
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3.
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Which
of the following reactions is an example of electron capture?
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4.
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If a
nucleus undergoes positron emission a. | its atomic number decreases by one and its mass number is
unchanged. | b. | its atomic number is unchanged and its mass number increases by
one. | c. | both its atomic
number and its mass number are unchanged. | d. | its atomic number increases by one and its mass number is
unchanged. | e. | its atomic number is unchanged and its mass number decreases by
one. | | |
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5.
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If a
nucleus emits an alpha particle a. | its atomic number decreases by four and its mass number
decreases by two. | b. | its atomic number decreases by two and its mass number
decreases by four. | c. | its atomic number decreases by two and its mass number
decreases by two. | d. | its atomic number decreases by four and its mass number is
unchanged. | e. | its atomic number is unchanged and its mass number decreases by
four. | | |
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6.
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If a
nucleus gains a neutron and then undergoes beta emission, a. | its atomic
number decreases by one and its mass number increases by one. | b. | its atomic
number is unchanged and its mass number increases by one. | c. | both its atomic
number and its mass number are unchanged. | d. | its atomic number increases by one and its mass number is
unchanged. | e. | its atomic number increases by one and its mass number
increases by one. | | |
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7.
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If a
nucleus decays by successive b, a, a emissions, its atomic number will a. | decrease by eight. | b. | decrease by
seven. | c. | decrease by four. | d. | decrease by
three. | e. | decrease by two. | | |
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8.
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If
Ag-106 decays by electron capture, what is the product?
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9.
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Complete the following nuclear reaction.
→
 + _____
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10.
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By
what (single step) process does polonium-211 decay to lead-207? a. | a particle emission | b. | b particle emission | c. | positron
emission | d. | electron capture | e. | neutron
capture | | |
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11.
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Strontium-90 has a half-life of 28.1 years. Starting with 2.08 mg of this isotope, how
much would remain after 112.4 years? a. | 0.13 mg | b. | 0.26
mg | c. | 0.52
mg | d. | 1.04
mg | e. | 1.56
mg | | |
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12.
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The
half-life of iodine-123 is 13.2 hours. What percentage of iodine-123 remains in a sample after 36
hours? a. | 13% | b. | 15% | c. | 37% | d. | 85% | e. | 95% | | |
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13.
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The
half-life of carbon-14 is 5730 years. What percentage of carbon-14 remains in a sample after 7.00
half-lives? a. | 0.78% | b. | 1.6% | c. | 3.1% | d. | 6.3% | e. | 14% | | |
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14.
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What
is the half-life of an isotope if the decay constant is 7.2
x
10-4 s-1? a. | 1.0
x 10-3
s | b. | 1.4 x 10-3
s | c. | 2.4
x 10-3
s | d. | 4.2
x 102
s | e. | 9.6
x 102
s | | |
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15.
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Carbon-14 dating is only accurate for samples less than 4.0
x 104
years old. If a sample initially contains 3.5 mg C-14, what mass remains after 4.0
x 104
years? The half-life of carbon-14 is 5730 years. a. | 1.4
x
10-8 g | b. | 7.9 x 10-6
g | c. | 2.8 x
10-5
g | d. | 5.1
x 10-5
g | e. | 5.0
x 10-4
g | | |
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16.
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A
sample of fluorine-18 is found to have an activity of 980 disintegrations per second (dps). After 8.0
hours the activity has decreased to 45 dps. What is the half-life, in years, for the decay of
fluorine-18? a. | 5.9
x 10-3
hr | b. | 0.39
hr | c. | 1.8
hr | d. | 4.1
hr | e. | 1.2 x 102
hr | | |
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17.
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Enriched uranium is uranium that has a greater proportion of ____. a. | lead-207 | b. | uranium-235 | c. | uranium-238 | d. | radium-226 | e. | plutonium-248 | | |
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18.
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Which
two nuclei are the two fissionable isotopes most commonly used in nuclear reactors?
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19.
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Complete the following fusion reaction.
_____
a. | | b. | 2  | c. | | d. | | e. | | | |
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20.
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Which
of the following isotopes is used in the treatment of thyroid disorders?
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