Question 1

Radioactive decay follows zero-order kinetics.

Accepted Answer

A) True 
 B)False

Question 2

In living organisms, C-14 atoms disintegrate at a rate of 15.3 atoms per minute per gram of carbon. A charcoal sample from an archaeological site has a C-14 disintegration rate of 9.16 atoms per minute per gram of carbon. Estimate the age of this sample. The half-life of C-14 is 5730 years.

Accepted Answer

A)  3170 years
B)  3430 years
C)  4020 years
D)  4790 years
E)  6750 yearsF) A) and D)
G) C) and D)

Question 3

Which of the following series of radioactive decays would convert Pa-234 to Ra-226?

Accepted Answer

A)  Beta, Alpha, Beta
B)  Alpha, Alpha
C)  Beta, Alpha, Alpha, Beta
D)  Beta, Alpha, Alpha
E)  Alpha, Beta, GammaF) A) and E)
G) A) and D)

Question 4

The radioisotope  will decay through

Accepted Answer

A)  α decay.
B)  β decay.
C)  γ decay.
D)  electron capture.
E)  spontaneous fission.F) A) and B)
G) D) and E)

Question 5

The isotope  has a half-life of 21 hours. If a sample initially contains exactly 10000 atoms of  , approximately how many of these atoms will remain after one week?

Accepted Answer

A)  1250
B)  78
C)  39
D)  0
E)  None of these choices are correct.F) A) and D)
G) A) and C)

Question 6

A scintillation counter

Accepted Answer

A)  measures the signal coming from an ionized gas.
B)  measures light emissions from excited atoms.
C)  depends on an avalanche of electrons generated as a particle moves through a tube of argon gas.
D)  detects high energy radiation better than low energy radiation.
E)  detects an electric current in a gas.F) A) and B)
G) A) and C)

Question 7

A pure sample of tritium, 3H, was prepared and sealed in a container for a number of years. Tritium undergoes β decay with a half-life of 12.32 years. How long has the container been sealed if analysis of the contents shows there are 5.25 mol of 3H and 6.35 mol of 3He present?

Accepted Answer

A)  2.34 y
B)  3.38 y
C)  9.77 y
D)  14.1 y
E)  25.6 yF) A) and B)
G) A) and C)

Question 8

Which of the following materials is put into a nuclear reactor to slow the chain reaction?

Accepted Answer

A)  Heavy water
B)  Moderators
C)  Control rods
D)  Reflectors
E)  ChlorineF) A) and E)
G) A) and D)

Question 9

Iodine-131, t1/2 = 8.0 days, is used in diagnosis and treatment of thyroid gland diseases. If a laboratory sample of iodine-131 initially emits 9.95 × 1018 β particles per day, how long will it take for the activity to drop to 6.22 × 1017 β particles per day?

Accepted Answer

A)  2.0 days
B)  16 days
C)  32 days
D)  128 days
E)  None of these choices are correct.F) All of the above
G) A) and E)

Question 10

The isotope 8" class="answers-bank-image d-inline" rel="preload" > has a half-life of 7.5 seconds. If a sample contains 144 atoms of 8" class="answers-bank-image d-inline" rel="preload" > approximately how many such atoms were there present 30 seconds earlier?

Accepted Answer

A)  576
B)  1152
C)  2304
D)  4320
E)  4.30 × 10 8F) All of the above
G) A) and C)

Question 11

A patient's thyroid gland is to be exposed to an average of 5.5 µCi for 16 days as an ingested sample of iodine-131 decays. If the energy of the β radiation is 9.7 × 10-14 J and the mass of the thyroid is 32.0 g, what is the dose received by the patient?

Accepted Answer

A)  0.027 rads
B)  1.2 rads
C)  37 rads
D)  85 rads
E)  None of these choices are correct.F) B) and E)
G) A) and B)

Question 12

Which of the following cannot be an example of nuclear fusion?

Accepted Answer

A)  A nuclear reaction in which two reactants have greater binding energy than their fused product.
B)  A nuclear reaction in which a carbon nucleus is produced.
C)  The primary energy-producing reaction in the Sun.
D)  The primary energy-producing reaction in a hydrogen bomb.
E)  A reaction in which the reactants are less stable than the products.F) B) and E)
G) B) and D)

Question 13

A 7.85 × 10-5 mol sample of copper-61 emits 1.47 × 1019 positrons in 90.0 minutes. What is the decay constant for copper-61?

Accepted Answer

A)  0.00230 h -1
B)  0.00346 h -1
C)  0.207 h -1
D)  0.311 h -1
E)  None of these choices are correct.F) A) and B)
G) A) and E)

Question 14

The radiochemist, Will I. Glow, studied thorium-232 and found that 2.82 × 10-7 moles emitted 8.42 × 106 α particles in one year. What is the decay constant for thorium-232?

Accepted Answer

A)  3.35 × 10 -14 yr -1
B)  4.96 × 10 -11 yr -1
C)  1.40 × 10 10 yr -1
D)  2.99 × 10 13 yr -1
E)  None of these choices are correct.F) B) and C)
G) A) and B)

Question 15

The radioisotope  will decay through

Accepted Answer

A)  α decay.
B)  β decay.
C)  positron decay.
D)  electron capture.
E)  γ decay.F) C) and E)
G) B) and E)

Question 16

The s-process involves a slow succession of neutron absorption and beta decay processes during the normal life of a star.

Accepted Answer

A) True 
 B)False

Question 17

An 85-kg person exposed to barium-141 receives 2.5 × 105 β particles, each with an energy of 5.2 × 10-13 J. How many rads does the person receive?

Accepted Answer

A)  2.4 × 10 -20
B)  1.5 × 10 -7
C)  1.8 × 10 -16
D)  6.1 × 10 -15
E)  None of these choices are correct.F) All of the above
G) A) and E)

Question 18

The isotope  is unstable. This is predictable because

Accepted Answer

A)  N/ Z ≠ 1.
B)  N/ Z is relatively low and Z 
C)  N/ Z is relatively large and Z 
D)  Z is small.
E)  N is large.F) A) and D)
G) None of the above

Question 19

So-called "magic numbers" of particles are thought to convey extra stability to certain nuclei. These magic numbers refer to which of the following particles?

Accepted Answer

A)  Protons only
B)  Electrons only
C)  Positrons only
D)  Neutrons only
E)  Protons and NeutronsF) C) and D)
G) A) and C)

Question 20

All the disintegrations of a sample of an unknown nuclide weighing 4.6 × 10-2 g were counted. In the first half-life of the sample, the total number of disintegrations counted was 4.3 × 1020. What is the atomic weight of the unknown element?

Accepted Answer

A)  32 amu
B)  16 amu
C)  8 amu
D)  4 amu
E)  None of these choices are correct.F) B) and C)
G) A) and B)

Exam 24: Nuclear Reactions and Their Applications

So-called "magic numbers" of particles are thought to convey extra stability to certain nuclei. These magic numbers refer to which of the following particles?

Correct AnswerverifiedShow Answer

The radioisotope will decay through

Correct AnswerverifiedShow Answer

Which of the following materials is put into a nuclear reactor to slow the chain reaction?

Correct AnswerverifiedShow Answer

Which of the following cannot be an example of nuclear fusion?

Correct AnswerverifiedShow Answer

Radioactive decay follows zero-order kinetics.

Correct AnswerverifiedShow Answer

The isotope has a half-life of 21 hours. If a sample initially contains exactly 10000 atoms of , approximately how many of these atoms will remain after one week?

Correct AnswerverifiedShow Answer

Which of the following series of radioactive decays would convert Pa-234 to Ra-226?

Correct AnswerverifiedShow Answer

In living organisms, C-14 atoms disintegrate at a rate of 15.3 atoms per minute per gram of carbon. A charcoal sample from an archaeological site has a C-14 disintegration rate of 9.16 atoms per minute per gram of carbon. Estimate the age of this sample. The half-life of C-14 is 5730 years.

Correct AnswerverifiedShow Answer

All the disintegrations of a sample of an unknown nuclide weighing 4.6 × 10-2 g were counted. In the first half-life of the sample, the total number of disintegrations counted was 4.3 × 1020. What is the atomic weight of the unknown element?

Correct AnswerverifiedShow Answer

A patient's thyroid gland is to be exposed to an average of 5.5 µCi for 16 days as an ingested sample of iodine-131 decays. If the energy of the β radiation is 9.7 × 10-14 J and the mass of the thyroid is 32.0 g, what is the dose received by the patient?

Correct AnswerverifiedShow Answer

The s-process involves a slow succession of neutron absorption and beta decay processes during the normal life of a star.

Correct AnswerverifiedShow Answer

The isotope has a half-life of 7.5 seconds. If a sample contains 144 atoms of approximately how many such atoms were there present 30 seconds earlier?

Correct AnswerverifiedShow Answer

An 85-kg person exposed to barium-141 receives 2.5 × 105 β particles, each with an energy of 5.2 × 10-13 J. How many rads does the person receive?

Correct AnswerverifiedShow Answer

The isotope is unstable. This is predictable because

Correct AnswerverifiedShow Answer

The radioisotope will decay through

Correct AnswerverifiedShow Answer

The radiochemist, Will I. Glow, studied thorium-232 and found that 2.82 × 10-7 moles emitted 8.42 × 106 α particles in one year. What is the decay constant for thorium-232?

Correct AnswerverifiedShow Answer

A scintillation counter

Correct AnswerverifiedShow Answer

A pure sample of tritium, 3H, was prepared and sealed in a container for a number of years. Tritium undergoes β decay with a half-life of 12.32 years. How long has the container been sealed if analysis of the contents shows there are 5.25 mol of 3H and 6.35 mol of 3He present?

Correct AnswerverifiedShow Answer

Iodine-131, t1/2 = 8.0 days, is used in diagnosis and treatment of thyroid gland diseases. If a laboratory sample of iodine-131 initially emits 9.95 × 1018 β particles per day, how long will it take for the activity to drop to 6.22 × 1017 β particles per day?

Correct AnswerverifiedShow Answer

A 7.85 × 10-5 mol sample of copper-61 emits 1.47 × 1019 positrons in 90.0 minutes. What is the decay constant for copper-61?

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

All the disintegrations of a sample of an unknown nuclide weighing 4.6 × 10^-²g were counted. In the first half-life of the sample, the total number of disintegrations counted was 4.3 × 10²⁰. What is the atomic weight of the unknown element?

Correct Answer
verified

A patient's thyroid gland is to be exposed to an average of 5.5 µCi for 16 days as an ingested sample of iodine-131 decays. If the energy of the β radiation is 9.7 × 10^-¹⁴ J and the mass of the thyroid is 32.0 g, what is the dose received by the patient?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

An 85-kg person exposed to barium-141 receives 2.5 × 10⁵ β particles, each with an energy of 5.2 × 10^-¹³ J. How many rads does the person receive?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

The radiochemist, Will I. Glow, studied thorium-232 and found that 2.82 × 10^-⁷moles emitted 8.42 × 10⁶ α particles in one year. What is the decay constant for thorium-232?

Correct Answer
verified

Correct Answer
verified

A pure sample of tritium, ³H, was prepared and sealed in a container for a number of years. Tritium undergoes β decay with a half-life of 12.32 years. How long has the container been sealed if analysis of the contents shows there are 5.25 mol of ³H and 6.35 mol of ³He present?

Correct Answer
verified

Iodine-131, t_1/2 = 8.0 days, is used in diagnosis and treatment of thyroid gland diseases. If a laboratory sample of iodine-131 initially emits 9.95 × 10¹⁸ β particles per day, how long will it take for the activity to drop to 6.22 × 10¹⁷ β particles per day?

Correct Answer
verified

A 7.85 × 10^-⁵ mol sample of copper-61 emits 1.47 × 10¹⁹ positrons in 90.0 minutes. What is the decay constant for copper-61?

Correct Answer
verified