Question 1

A radioisotope has a half-life of τ at a temperature of 150 K. If its temperature is increased to 300 K, what will its half-life be?

Accepted Answer

A)  4τ 
B)  2 τ 
C)  τ 
D)  τ/2 
E)  τ/4 
A)  4τ 
B)  2 τ 
C)  τ 
D)  τ/2 
E)  τ/4 C

Question 2

A radioactive isotope decays by β- emission with a half-life of 1.0 min. During the first 1.0 min, a particular sample emits 1000 β- particles. During the next 1.0 min, the number of β- particles this sample will emit will be closest to

Accepted Answer

A)  250. 
B)  500. 
C)  1000. 
D)  1500. 
E)  2000. 
A)  250. 
B)  500. 
C)  1000. 
D)  1500. 
E)  2000. B

Question 3

The radioactive nuclei 60Co is widely used in medical applications. It undergoes beta decay, and the total energy of the decay process is 2.82 MeV per decay event. The half-life of this nucleus is 272 days. Suppose that a patient is given a dose of 6.9 µCi of 60Co. If all of this material decayed while in the patient's body, what would be the total energy deposited there? (1 Ci = 3.70 × 1010 decays/s)

Accepted Answer

A)  11 J 
B)  8.6 GJ 
C)  3.9 J 
D)  24 J 
E)  4.15 MJ 
A)  11 J 
B)  8.6 GJ 
C)  3.9 J 
D)  24 J 
E)  4.15 MJ C

Question 4

Two identical nuclei of mass 18 u are made to unite to make a single nucleus of mass 36 u. What is the radius of the result of this fusion?

Accepted Answer

A)  4.0 fm 
B)  6.3 fm 
C)  4.5 fm 
D)  7.2 fm 
A)  4.0 fm 
B)  6.3 fm 
C)  4.5 fm 
D)  7.2 fm

Question 5

The stability of   Fe with respect to alpha, β+, and β- decay is to be determined. Do not consider the possibility of decay by electron capture. The following atomic masses are known:   He: 4.002603 u   Cr: 51.944768 u   Mn: 55.938907 u   Fe: 55.934939 u   Co: 55.939841 u The   Fe nuclide is

Accepted Answer

A)  not subject to alpha, β+, or β- decay. 
B)  subject to alpha decay only. 
C)  subject to β+decay only. 
D)  subject to β- decay only. 
E)  subject to β+ or β- decay, but not to alpha decay. 
A)  not subject to alpha, β+, or β- decay. 
B)  subject to alpha decay only. 
C)  subject to β+decay only. 
D)  subject to β- decay only. 
E)  subject to β+ or β- decay, but not to alpha decay.

Question 6

A certain nucleus containing 8 protons and 7 neutrons has a radius R. Which of the following values would be closest to the expected value of the radius of a nucleus having 51 protons and 69 neutrons?

Accepted Answer

A)  1.85R 
B)  2.00R 
C)  2.14R 
D)  6.38R 
E)  8.00R 
A)  1.85R 
B)  2.00R 
C)  2.14R 
D)  6.38R 
E)  8.00R

Question 7

Radium-226 decays into radon-222 plus an alpha particle. How much energy is released in this process? 1 u = 931.494 MeV/c2, and the relevant mass values are   He: 4.002603 u   Rn: 222.017570 u   Ra: 226.025402 u

Accepted Answer

A)  4.24 MeV 
B)  3.76 MeV 
C)  4.87 MeV 
D)  5.05 MeV 
E)  5.39 MeV 
A)  4.24 MeV 
B)  3.76 MeV 
C)  4.87 MeV 
D)  5.05 MeV 
E)  5.39 MeV

Question 8

The maximum permissible workday dose for occupational exposure to radiation is 26 mrem. A 55-kg laboratory technician absorbs 3.3 mJ of 0.40-MeV gamma rays in a workday. The relative biological efficiency (RBE) for gamma rays is 1.00. What is the ratio of the equivalent dosage received by the technician to the maximum permissible equivalent dosage?

Accepted Answer

A)  0.23 
B)  0.25 
C)  0.28 
D)  0.30 
E)  0.32 
A)  0.23 
B)  0.25 
C)  0.28 
D)  0.30 
E)  0.32

Question 9

Consider the short-lived neutral isotope represented by   X. Which of the following statements about this isotope are correct? (There may be more than one correct choice.)

Accepted Answer

A)  The isotope has 25 nucleons. 
B)  The isotope has 25 protons. 
C)  The isotope has 25 neutrons. 
D)  The isotope has 15 orbital electrons. 
E)  The isotope has 15 protons.
F) The isotope has 10 neutrons. 
A)  The isotope has 25 nucleons. 
B)  The isotope has 25 protons. 
C)  The isotope has 25 neutrons. 
D)  The isotope has 15 orbital electrons. 
E)  The isotope has 15 protons.
F) The isotope has 10 neutrons.

Question 10

The carbon in your body was formed in nuclear reactions in long-dead stars. How much energy was released when three 4He nuclei combined to make 12C? The mass of 4He is 4.002603 u, the mass of 12C is 12.0000 u, and 1 u = 931.494 MeV/c2.

Accepted Answer

A)  7.274 MeV 
B)  3716 MeV 
C)  8.424 MeV 
D)  2.106 MeV 
A)  7.274 MeV 
B)  3716 MeV 
C)  8.424 MeV 
D)  2.106 MeV

Question 11

If a nucleus decays by alpha decay to a daughter nucleus, which of the following statements about this decay are correct? (There may be more than one correct choice.)

Accepted Answer

A)  The daughter nucleus has more protons than the original nucleus. 
B)  The daughter nucleus has more neutrons than the original nucleus. 
C)  The daughter nucleus has the same number of nucleons as the original nucleus. 
D)  The daughter nucleus has fewer protons than the original nucleus. 
E)  The daughter nucleus has fewer neutrons than the original nucleus. 
A)  The daughter nucleus has more protons than the original nucleus. 
B)  The daughter nucleus has more neutrons than the original nucleus. 
C)  The daughter nucleus has the same number of nucleons as the original nucleus. 
D)  The daughter nucleus has fewer protons than the original nucleus. 
E)  The daughter nucleus has fewer neutrons than the original nucleus.

Question 12

Which of the following statements about β+ decay are correct? (There may be more than one correct choice.) During β+ decay

Accepted Answer

A)  an orbital electron is captured by the nucleus. 
B)  a proton is emitted from the nucleus. 
C)  a neutron in the nucleus decays to a proton and an electron. 
D)  a proton in the nucleus decays to a positron and a neutron. 
E)  the atomic number Z of the isotope increases by one unit but the atomic weight A remains unchanged. 
A)  an orbital electron is captured by the nucleus. 
B)  a proton is emitted from the nucleus. 
C)  a neutron in the nucleus decays to a proton and an electron. 
D)  a proton in the nucleus decays to a positron and a neutron. 
E)  the atomic number Z of the isotope increases by one unit but the atomic weight A remains unchanged.

Question 13

The iron nucleus has the greatest binding energy of any nucleus.

Accepted Answer

A)  True 
B)  False 
A)  True 
B)  False

Question 14

The half-life of cobalt-60 is 5.3 years, while that of strontium-90 is 28 years. Suppose that samples of cobalt-60 and strontium-90 are such that they initially have the same activity (number of decays per second). What is true about the initial numbers of cobalt-60 and strontium-90 nuclei in these samples?

Accepted Answer

A)  There are more strontium-90 than cobalt-60 nuclei. 
B)  There are equal numbers of cobalt-60 and strontium-90 nuclei. 
C)  There are more cobalt-60 than strontium-90 nuclei. 
D)  It is not possible to compare numbers of nuclei without knowing the masses of the samples. 
A)  There are more strontium-90 than cobalt-60 nuclei. 
B)  There are equal numbers of cobalt-60 and strontium-90 nuclei. 
C)  There are more cobalt-60 than strontium-90 nuclei. 
D)  It is not possible to compare numbers of nuclei without knowing the masses of the samples.

Question 15

What would be the expected radius of a nucleus having 82 protons and 125 neutrons?

Accepted Answer

A)  5.2 fm 
B)  5.9 fm 
C)  6.0 fm 
D)  7.1 fm 
E)  17 fm 
A)  5.2 fm 
B)  5.9 fm 
C)  6.0 fm 
D)  7.1 fm 
E)  17 fm

Question 16

What is the binding energy per nucleon for   Al? The neutral   Al atom has a mass of 26.981539 u; a neutral hydrogen atom has a mass of 1.007825 u; a neutron has a mass of 1.008665 u; and a proton has a mass of 1.007277 u. (1 u = 931.494 MeV/c2)

Accepted Answer

A)  8.3 MeV 
B)  6.7 MeV 
C)  5.4 MeV 
D)  3.4 MeV 
E)  2.8 MeV 
A)  8.3 MeV 
B)  6.7 MeV 
C)  5.4 MeV 
D)  3.4 MeV 
E)  2.8 MeV

Question 17

Which of the following statements about the strong nuclear force are correct? (There may be more than one correct choice.)

Accepted Answer

A)  It acts equally on protons and neutrons but not on electrons. 
B)  It acts equally on protons, neutrons, and electrons. 
C)  It has a much longer range than the electric force. 
D)  It keeps electrons in their orbits around the nucleus. 
E)  Because of its very short range, there is a limit to how large the nucleus can be. 
A)  It acts equally on protons and neutrons but not on electrons. 
B)  It acts equally on protons, neutrons, and electrons. 
C)  It has a much longer range than the electric force. 
D)  It keeps electrons in their orbits around the nucleus. 
E)  Because of its very short range, there is a limit to how large the nucleus can be.

Question 18

Which of the following statements about the atomic nucleus is correct? (There may be more than one correct choice.)

Accepted Answer

A)  Large nuclei are denser than light nuclei. 
B)  All nuclei have nearly the same density. 
C)  The nucleus is held together more by the electrical force than by the gravitational force. 
D)  A nucleus containing 20 nucleons will have approximately twice the radius as a nucleus containing 10 nucleons. 
E)  As the number of nucleons increases the binding energy per nucleon always increases. 
A)  Large nuclei are denser than light nuclei. 
B)  All nuclei have nearly the same density. 
C)  The nucleus is held together more by the electrical force than by the gravitational force. 
D)  A nucleus containing 20 nucleons will have approximately twice the radius as a nucleus containing 10 nucleons. 
E)  As the number of nucleons increases the binding energy per nucleon always increases.

Question 19

Modern nuclear bomb tests have created an extra high level of 14C in our atmosphere. Suppose that future archaeologists date samples from our era, but do not know about this testing. Will their dates be too young, too old, or still correct? If correct they are correct, why?

Accepted Answer

A)  too young 
B)  too old 
C)  correct, because 14C from bomb tests is different from that produced naturally 
D)  correct, because modern biological materials do not gather 14C from bomb tests 
A)  too young 
B)  too old 
C)  correct, because 14C from bomb tests is different from that produced naturally 
D)  correct, because modern biological materials do not gather 14C from bomb tests

Question 20

A radioactive atom has 98 protons and 249 nucleons. If it undergoes alpha decay, what are the number of protons and nucleons, respectively, in the daughter nucleus?

Accepted Answer

A)  100, 245 
B)  94, 247 
C)  96, 245 
D)  96, 247 
E)  100, 249 
A)  100, 245 
B)  94, 247 
C)  96, 245 
D)  96, 247 
E)  100, 249

Exam 42: Nuclear Physics

A radioisotope has a half-life of τ at a temperature of 150 K. If its temperature is increased to 300 K, what will its half-life be?

A radioactive isotope decays by β- emission with a half-life of 1.0 min. During the first 1.0 min, a particular sample emits 1000 β- particles. During the next 1.0 min, the number of β- particles this sample will emit will be closest to

Two identical nuclei of mass 18 u are made to unite to make a single nucleus of mass 36 u. What is the radius of the result of this fusion?

The stability of Fe with respect to alpha, β+, and β- decay is to be determined. Do not consider the possibility of decay by electron capture. The following atomic masses are known: He: 4.002603 u Cr: 51.944768 u Mn: 55.938907 u Fe: 55.934939 u Co: 55.939841 u The Fe nuclide is

A certain nucleus containing 8 protons and 7 neutrons has a radius R. Which of the following values would be closest to the expected value of the radius of a nucleus having 51 protons and 69 neutrons?

Radium-226 decays into radon-222 plus an alpha particle. How much energy is released in this process? 1 u = 931.494 MeV/c2, and the relevant mass values are He: 4.002603 u Rn: 222.017570 u Ra: 226.025402 u

Consider the short-lived neutral isotope represented by X. Which of the following statements about this isotope are correct? (There may be more than one correct choice.)

The carbon in your body was formed in nuclear reactions in long-dead stars. How much energy was released when three 4He nuclei combined to make 12C? The mass of 4He is 4.002603 u, the mass of 12C is 12.0000 u, and 1 u = 931.494 MeV/c2.

If a nucleus decays by alpha decay to a daughter nucleus, which of the following statements about this decay are correct? (There may be more than one correct choice.)

Which of the following statements about β+ decay are correct? (There may be more than one correct choice.) During β+ decay

The iron nucleus has the greatest binding energy of any nucleus.

What would be the expected radius of a nucleus having 82 protons and 125 neutrons?

What is the binding energy per nucleon for Al? The neutral Al atom has a mass of 26.981539 u; a neutral hydrogen atom has a mass of 1.007825 u; a neutron has a mass of 1.008665 u; and a proton has a mass of 1.007277 u. (1 u = 931.494 MeV/c2)

Which of the following statements about the strong nuclear force are correct? (There may be more than one correct choice.)

Which of the following statements about the atomic nucleus is correct? (There may be more than one correct choice.)

Modern nuclear bomb tests have created an extra high level of 14C in our atmosphere. Suppose that future archaeologists date samples from our era, but do not know about this testing. Will their dates be too young, too old, or still correct? If correct they are correct, why?

A radioactive atom has 98 protons and 249 nucleons. If it undergoes alpha decay, what are the number of protons and nucleons, respectively, in the daughter nucleus?

Concepts of Motion

Kinematics in One Dimension

Vectors and Coordinate Systems

Kinematics in Two Dimensions

Force and Motion

Dynamics I: Motion Along a Line

Newtons Third Law

Dynamics Ii: Motion in a Plane

Work and Kinetic Energy

Interactions and Potential Energy

Impulse and Momentum

Rotation of a Rigid Body

Newtons Theory of Gravity

Fluids and Elasticity

Oscillations

Traveling Waves

Superposition

A Macroscopic Description of Matter

Work, Heat, and the First Law of Thermodynamics

The Micromacro Connection

Heat Engines and Refrigerators

Electric Charges and Forces

The Electric Field

Gausss Law

The Electric Potential

Potential and Field

Current and Resistance

Fundamentals of Circuits

The Magnetic Field

Electromagnetic Induction

Electromagnetic Fields and Waves

Ac Circuits

Wave Optics

Ray Optics

Optical Instruments

Relativity

The Foundations of Modern Physics

Quantization

Wave Functions and Uncertainty

One-Dimensional Quantum Mechanics

Atomic Physics

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A radioactive isotope decays by β^- emission with a half-life of 1.0 min. During the first 1.0 min, a particular sample emits 1000 β^- particles. During the next 1.0 min, the number of β^- particles this sample will emit will be closest to

The stability of Fe with respect to alpha, β⁺, and β^-decay is to be determined. Do not consider the possibility of decay by electron capture. The following atomic masses are known: He: 4.002603 u Cr: 51.944768 u Mn: 55.938907 u Fe: 55.934939 u Co: 55.939841 u The Fe nuclide is

Radium-226 decays into radon-222 plus an alpha particle. How much energy is released in this process? 1 u = 931.494 MeV/c², and the relevant mass values are He: 4.002603 u Rn: 222.017570 u Ra: 226.025402 u

The carbon in your body was formed in nuclear reactions in long-dead stars. How much energy was released when three ⁴He nuclei combined to make ¹²C? The mass of ⁴He is 4.002603 u, the mass of ¹²C is 12.0000 u, and 1 u = 931.494 MeV/c².

Which of the following statements about β⁺ decay are correct? (There may be more than one correct choice.) During β⁺ decay

What is the binding energy per nucleon for Al? The neutral Al atom has a mass of 26.981539 u; a neutral hydrogen atom has a mass of 1.007825 u; a neutron has a mass of 1.008665 u; and a proton has a mass of 1.007277 u. (1 u = 931.494 MeV/c²)

Modern nuclear bomb tests have created an extra high level of ¹⁴C in our atmosphere. Suppose that future archaeologists date samples from our era, but do not know about this testing. Will their dates be too young, too old, or still correct? If correct they are correct, why?