Question 1

The fact that the binding energy per nucleon does not depend very strongly on the volume of the nucleus indicates that:

Accepted Answer

A)  the strong nuclear force saturates.
B)  nucleons don't move throughout the nucleus.
C)  all nuclei have the same volume.
D)  the radius of a nucleus is directly proportional to the number of nucleons.E) All of the above
F) A) and C)

Question 2

The isotope 14C cannot be used in dating old samples of which of the following?

Accepted Answer

A)  charcoal from a fire
B)  a bronze implement from a cave
C)  a bone buried in mud
D)  All of the above can be dated using 14C.E) A) and C)
F) B) and C) B

Question 3

A radioactive isotope that emits a gamma quantum will change in what respect?

Accepted Answer

A)  Atomic number increases by one.
B)  Atomic number decreases by one.
C)  Atomic mass number decreases by one.
D)  None of the above choices are valid.E) All of the above
F) None of the above

Question 4

What particle is emitted when 20Na decays to 20Ne? (atomic numbers of Na and Ne are, respectively, 11 and 10)

Accepted Answer

A)  alpha
B)  beta (electron) 
C)  beta (positron) 
D)  gamma quantumE) A) and B)
F) B) and C)

Question 5

Tritium has a half-life of 12.3 years.How many years will elapse when the radioactivity of a tritium sample diminishes to 20% of its original value?

Accepted Answer

A)  21 years
B)  29 years
C)  57 years
D)  86 yearsE) C) and D)
F) B) and D)

Question 6

The Q value of the reaction  is -1.65 MeV.What is the threshold energy of this reaction? (Hint: Once the Q value is known, the relative mass numbers are precise enough to yield the result to 3 significant figures, actual masses not being needed) .

Accepted Answer

A)  1.65 MeV
B)  1.89 MeV
C)  1.77 MeV
D)  1.41 MeVE) A) and C)
F) A) and B)

Question 7

A radioactive material initially is observed to have an activity of 1 000 decays/sec.If three hours later it is observed to have an activity of 125 decays/sec, what is its half-life?

Accepted Answer

A)  1/2 hour
B)  1 hour
C)  3 hours
D)  8 hoursE) A) and D)
F) A) and C)

Question 8

What energy must be added or given off in a reaction where two hydrogen atoms and two neutrons are combined to form a helium atom? (Atomic masses for each: hydrogen, 1.007 825 u; neutron, 1.008 665 u; helium, 4.002 602 u; also, 1 u = 931.5 MeV/c2)

Accepted Answer

A)  20.7 MeV added
B)  20.7 MeV given off
C)  28.3 MeV given off
D)  28.3 MeV addedE) A) and B)
F) A) and C)

Question 9

The binding energy of a nucleus is equal to:

Accepted Answer

A)  the energy needed to remove one of the nucleons.
B)  the average energy with which any nucleon is bound in the nucleus.
C)  the energy needed to separate all the nucleons from each other.
D)  the mass of the nucleus times c2.E) C) and D)
F) A) and C)

Question 10

To what is the radiation damage in biological organisms primarily due?

Accepted Answer

A)  helium introduction
B)  heating
C)  induced radioactivity
D)  ionizationE) B) and C)
F) A) and C)

Question 11

In the beta decay of 14C, the existence of the antineutrino was required to maintain:

Accepted Answer

A)  energy conservation.
B)  charge conservation.
C)  conservation of the number of nucleons.
D)  all of the above.E) All of the above
F) B) and D)

Question 12

The alpha emission process results in the daughter nucleus differing in what manner from the parent?

Accepted Answer

A)  Atomic mass increases by one.
B)  Atomic number decreases by two.
C)  Atomic number increases by one.
D)  Atomic mass decreases by two.E) A) and B)
F) A) and C) B

Question 13

An element is emitting alpha, beta, and gamma radiation.Rank order them in terms of the thickness of protective shielding they will need for safety, from least to most.

Accepted Answer

A)  alpha, beta and gamma
B)  gamma, beta and alpha
C)  beta, gamma and alpha
D)  alpha, gamma and betaE) None of the above
F) A) and B)

Question 14

The mass of 238U is not quite an integer multiple of 1H mass.This is primarily because:

Accepted Answer

A)  the proton and neutron have different masses.
B)  there are several isotopes of uranium.
C)  of the binding energy of uranium.
D)  uranium is radioactive.E) All of the above
F) C) and D) C

Question 15

For every stable nucleus except hydrogen, if the number of nucleons is doubled, the quantity that will change least is the:

Accepted Answer

A)  mass.
B)  charge.
C)  volume.
D)  density.E) A) and B)
F) B) and D)

Question 16

The atomic number of a given element is equivalent to which of the following?

Accepted Answer

A)  proton number in the nucleus
B)  neutron number in the nucleus
C)  sum of the protons and neutrons in the nucleus
D)  number of electrons in the outer shellsE) A) and C)
F) A) and D)

Question 17

Sample #1 is made from an isotope with decay constant  and sample #2 is made from an isotope with decay constant  , where  .Which of the following statements must be true?

Accepted Answer

A)  The activity of sample #1 is greater than that of sample #2.
B)  The activity of sample #2 is greater than that of sample #1.
C)  The half-life exhibited for sample #1 is greater than that of sample #2.
D)  The half-life exhibited for sample #2 is greater than that for sample #1E) A) and C)
F) B) and D)

Question 18

The isotope 64Zn has a nuclear radius of 4.8 * 10-15 m.Approximately what is the nuclear radius of the isotope 27Al?

Accepted Answer

A)  2.0 * 10-15 m
B)  2.7 * 10-15 m
C)  3.6 * 10-15 m
D)  4.0 * 10-15 mE) C) and D)
F) B) and D)

Question 19

The existence of the neutrino was postulated to account for which basic conservation laws during the beta decay process?

Accepted Answer

A)  conservation of energy
B)  conservation of momentum
C)  Both choices a and b are valid.
D)  None of the above choices are valid.E) All of the above
F) A) and B)

Question 20

The isotope 238U, which starts one of the natural radioactive series, decays first by alpha decay followed by two negative beta decays.At this point, what is the resulting isotope?

Accepted Answer

A)  (238U) 
B)  (236U) 
C)  (234Th (Z = 90 for Th.) ) 
D)  Some other uranium isotope not given above.E) B) and C)
F) A) and C)

Exam 29: Nuclear Physics

The fact that the binding energy per nucleon does not depend very strongly on the volume of the nucleus indicates that:

Correct AnswerverifiedShow Answer

The isotope 14C cannot be used in dating old samples of which of the following?

Correct AnswerverifiedB

A radioactive isotope that emits a gamma quantum will change in what respect?

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What particle is emitted when 20Na decays to 20Ne? (atomic numbers of Na and Ne are, respectively, 11 and 10)

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Tritium has a half-life of 12.3 years.How many years will elapse when the radioactivity of a tritium sample diminishes to 20% of its original value?

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The Q value of the reaction is -1.65 MeV.What is the threshold energy of this reaction? (Hint: Once the Q value is known, the relative mass numbers are precise enough to yield the result to 3 significant figures, actual masses not being needed) .

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A radioactive material initially is observed to have an activity of 1 000 decays/sec.If three hours later it is observed to have an activity of 125 decays/sec, what is its half-life?

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What energy must be added or given off in a reaction where two hydrogen atoms and two neutrons are combined to form a helium atom? (Atomic masses for each: hydrogen, 1.007 825 u; neutron, 1.008 665 u; helium, 4.002 602 u; also, 1 u = 931.5 MeV/c2)

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The binding energy of a nucleus is equal to:

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To what is the radiation damage in biological organisms primarily due?

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In the beta decay of 14C, the existence of the antineutrino was required to maintain:

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The alpha emission process results in the daughter nucleus differing in what manner from the parent?

Correct AnswerverifiedB

An element is emitting alpha, beta, and gamma radiation.Rank order them in terms of the thickness of protective shielding they will need for safety, from least to most.

Correct AnswerverifiedShow Answer

The mass of 238U is not quite an integer multiple of 1H mass.This is primarily because:

Correct AnswerverifiedC

For every stable nucleus except hydrogen, if the number of nucleons is doubled, the quantity that will change least is the:

Correct AnswerverifiedShow Answer

The atomic number of a given element is equivalent to which of the following?

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Sample #1 is made from an isotope with decay constant and sample #2 is made from an isotope with decay constant , where .Which of the following statements must be true?

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The isotope 64Zn has a nuclear radius of 4.8 * 10-15 m.Approximately what is the nuclear radius of the isotope 27Al?

Correct AnswerverifiedShow Answer

The existence of the neutrino was postulated to account for which basic conservation laws during the beta decay process?

Correct AnswerverifiedShow Answer

The isotope 238U, which starts one of the natural radioactive series, decays first by alpha decay followed by two negative beta decays.At this point, what is the resulting isotope?

Correct AnswerverifiedShow Answer

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The isotope ¹⁴C cannot be used in dating old samples of which of the following?

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B

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What particle is emitted when ²⁰Na decays to ²⁰Ne? (atomic numbers of Na and Ne are, respectively, 11 and 10)

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What energy must be added or given off in a reaction where two hydrogen atoms and two neutrons are combined to form a helium atom? (Atomic masses for each: hydrogen, 1.007 825 u; neutron, 1.008 665 u; helium, 4.002 602 u; also, 1 u = 931.5 MeV/c²)

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In the beta decay of ¹⁴C, the existence of the antineutrino was required to maintain:

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B

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The mass of ²³⁸U is not quite an integer multiple of ¹H mass.This is primarily because:

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C

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The isotope ⁶⁴Zn has a nuclear radius of 4.8 * 10^-15 m.Approximately what is the nuclear radius of the isotope ²⁷Al?

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The isotope ²³⁸U, which starts one of the natural radioactive series, decays first by alpha decay followed by two negative beta decays.At this point, what is the resulting isotope?

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