Question 1

Rutherfordium-261 has a half-life of 1.08 min.How long will it take for a sample of rutherfordium to lose one-third of its nuclei?

Accepted Answer

A)  1.02 min 
B)  1.62 min 
C)  0.632 min 
D)  2.70 min 
E)  3.24 min 
A)  1.02 min 
B)  1.62 min 
C)  0.632 min 
D)  2.70 min 
E)  3.24 min

Question 2

Fermium-253 has a half-life of 3.00 d.A sample of fermium contains 7.37 ×   nuclei.How long will it take for there to be only 3.36 ×   fermium nuclei in this sample?

Accepted Answer

A)  2.75 d 
B)  9.80 d 
C)  13.4 d 
D)  15.7 d 
E)  58.6 d 
A)  2.75 d 
B)  9.80 d 
C)  13.4 d 
D)  15.7 d 
E)  58.6 d

Question 3

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 4

The decay rate of an isotope is initially R0,but after one half-life has gone by,the rate is R0/2.At the end of the NEXT half-life,what will the decay rate be?

Accepted Answer

A)  0 
B)  R0/16 
C)  R0/e 
D)  R0/4 
E)  R0/e2 
A)  0 
B)  R0/16 
C)  R0/e 
D)  R0/4 
E)  R0/e2

Question 5

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

Question 6

Calculate the reaction energy (Q value)for the reaction 7Li + 1H → 4He + 4He,given the following masses: 7Li: 7.016005 u
1H: 1.007825 u
4He: 4.002603 u
(1 u = 931.5 MeV/c2)

Accepted Answer

A)  13.35 MeV 
B)  13.57 MeV 
C)  15.37 MeV 
D)  17.35 MeV 
E)  17.53 MeV 
A)  13.35 MeV 
B)  13.57 MeV 
C)  15.37 MeV 
D)  17.35 MeV 
E)  17.53 MeV

Question 7

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 8

How much energy is released when 1.40 μg of 3H have decayed to 3He? The mass of 3He is 3.016029 u,the mass of 3H is 3.016049 u,and 1 u = 931.494 MeV/c2.

Accepted Answer

A)  830 J 
B)  11,900 J 
C)  7970 J 
D)  71,700 J 
E)  23,900 J 
A)  830 J 
B)  11,900 J 
C)  7970 J 
D)  71,700 J 
E)  23,900 J

Question 9

A 57-kg researcher absorbs 6.3 ×   neutrons in a workday.The energy of the neutrons is 2.6 MeV.The relative biological efficiency (RBE)for fast neutrons is 10.What is the equivalent dosage of the radiation exposure,in mrem,of this worker?

Accepted Answer

A)  4.6 mrem 
B)  1.4 mrem 
C)  2.9 mrem 
D)  14 mrem 
E)  46 mrem 
A)  4.6 mrem 
B)  1.4 mrem 
C)  2.9 mrem 
D)  14 mrem 
E)  46 mrem

Question 10

If a nucleus decays by β- 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 11

The following masses are known:   n (neutron)1.008665 u   H 1.007825 u   Fe 56.935399 u What is the binding energy of   Fe,in MeV? (1 u = 1.6605 × 10-27 kg =

Accepted Answer

A)  500 MeV 
B)  550 MeV 
C)  610 MeV 
D)  660 MeV 
E)  710 MeV 
A)  500 MeV 
B)  550 MeV 
C)  610 MeV 
D)  660 MeV 
E)  710 MeV

Question 12

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 13

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.

Question 14

The half-life of cobalt-60 is 5.3 years,while that of strontium-90 is 28 years.Suppose you have a sample of each,such that they initially contain equal numbers of atoms of these nuclides.How will the activities (number of decays per second)of the samples compare?

Accepted Answer

A)  The activity of the cobalt-60 sample will be greater. 
B)  The activities cannot be compared without more information. 
C)  The activities will be equal. 
D)  The activity of the strontium-90 sample will be greater. 
A)  The activity of the cobalt-60 sample will be greater. 
B)  The activities cannot be compared without more information. 
C)  The activities will be equal. 
D)  The activity of the strontium-90 sample will be greater.

Question 15

A sphere made of a radioactive isotope initially has a mass of 6.88 kg.The half-life of this isotope is 1.34 h,and it decays by β- emission.At the end of 2.68 h,what is the mass of this sphere?

Accepted Answer

A)  6.88 kg 
B)  3.44 kg 
C)  1.72 kg 
D)  2.53 kg 
A)  6.88 kg 
B)  3.44 kg 
C)  1.72 kg 
D)  2.53 kg

Question 16

If a nucleus had a diameter of 8.0 fm,what would be its expected mass,in atomic mass units?

Accepted Answer

A)  7 u 
B)  296 u 
C)  37 u 
D)  64 u 
E)  128 u 
A)  7 u 
B)  296 u 
C)  37 u 
D)  64 u 
E)  128 u

Question 17

When a neutron (n)collides with a uranium-235 nucleus it can induce a variety of fission reactions.One such reaction is   U + n →   Xe +   Sr + 2n.How much energy is released in this reaction,given the following mass values:   Xe: 139.921620 u   Sr : 93.915367 u   U: 235.043924 u n: 1.008665 u
(1 u = 931.494 MeV/c2)

Accepted Answer

A)  185 MeV 
B)  202 MeV 
C)  32.6 MeV 
D)  65.7 MeV 
E)  98.6 MeV 
A)  185 MeV 
B)  202 MeV 
C)  32.6 MeV 
D)  65.7 MeV 
E)  98.6 MeV

Question 18

Two deuterium nuclei,   H,fuse to produce a helium nucleus,   H,and a neutron.A neutral deuterium atom has a mass of 2.014102 u; a neutral helium atom has a mass of 3.016030 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 1.007276 u.How much energy is released in the process?

Accepted Answer

A)  3.27 MeV 
B)  3.57 MeV 
C)  4.00 MeV 
D)  4.50 MeV 
E)  5.68 MeV 
A)  3.27 MeV 
B)  3.57 MeV 
C)  4.00 MeV 
D)  4.50 MeV 
E)  5.68 MeV

Question 19

For the missing product X in the reaction
neutron +   U →   Ba + X + 3 neutrons
determine the atomic mass and atomic number of X,and write X in the standard form.It is NOT necessary to identify which atom X is.

Accepted Answer

The answer of For the missing product X in the...

Question 20

An air sample is contaminated with 15O,which has a half-life of 2.03 min.One possible way to minimize its hazard is to pass it through a long pipe to allow it to decay inside the pipe until it can be safely released into the atmosphere.If the oxygen moves at a speed of 1.1 m/s in the pipe,how long must the pipe be for the sample to have decayed to 3.0% of its original activity just as it leaves the pipe?

Accepted Answer

A)  680 m 
B)  8.0 m 
C)  7.0 m 
D)  2.0 m 
A)  680 m 
B)  8.0 m 
C)  7.0 m 
D)  2.0 m

Exam 43: Nuclear Physics

Rutherfordium-261 has a half-life of 1.08 min.How long will it take for a sample of rutherfordium to lose one-third of its nuclei?

Fermium-253 has a half-life of 3.00 d.A sample of fermium contains 7.37 × nuclei.How long will it take for there to be only 3.36 × fermium nuclei in this sample?

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

The decay rate of an isotope is initially R0,but after one half-life has gone by,the rate is R0/2.At the end of the NEXT half-life,what will the decay rate be?

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?

Calculate the reaction energy (Q value)for the reaction 7Li + 1H → 4He + 4He,given the following masses: 7Li: 7.016005 u 1H: 1.007825 u 4He: 4.002603 u (1 u = 931.5 MeV/c2)

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

How much energy is released when 1.40 μg of 3H have decayed to 3He? The mass of 3He is 3.016029 u,the mass of 3H is 3.016049 u,and 1 u = 931.494 MeV/c2.

A 57-kg researcher absorbs 6.3 × neutrons in a workday.The energy of the neutrons is 2.6 MeV.The relative biological efficiency (RBE)for fast neutrons is 10.What is the equivalent dosage of the radiation exposure,in mrem,of this worker?

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

The following masses are known: n (neutron)1.008665 u H 1.007825 u Fe 56.935399 u What is the binding energy of Fe,in MeV? (1 u = 1.6605 × 10-27 kg =

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?

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 half-life of cobalt-60 is 5.3 years,while that of strontium-90 is 28 years.Suppose you have a sample of each,such that they initially contain equal numbers of atoms of these nuclides.How will the activities (number of decays per second)of the samples compare?

A sphere made of a radioactive isotope initially has a mass of 6.88 kg.The half-life of this isotope is 1.34 h,and it decays by β- emission.At the end of 2.68 h,what is the mass of this sphere?

If a nucleus had a diameter of 8.0 fm,what would be its expected mass,in atomic mass units?

For the missing product X in the reaction neutron + U → Ba + X + 3 neutrons determine the atomic mass and atomic number of X,and write X in the standard form.It is NOT necessary to identify which atom X is.

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Filters

The decay rate of an isotope is initially R₀,but after one half-life has gone by,the rate is R₀/2.At the end of the NEXT half-life,what will the decay rate be?

Calculate the reaction energy (Q value)for the reaction ⁷Li +¹H → ⁴He + ⁴He,given the following masses: ⁷Li: 7.016005 u ¹H: 1.007825 u ⁴He: 4.002603 u (1 u = 931.5 MeV/c²)

How much energy is released when 1.40 μg of ³H have decayed to ³He? The mass of ³He is 3.016029 u,the mass of ³H is 3.016049 u,and 1 u = 931.494 MeV/c².

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

The following masses are known: n (neutron)1.008665 u H 1.007825 u Fe 56.935399 u What is the binding energy of Fe,in MeV? (1 u = 1.6605 × 10^-27 kg =

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

A sphere made of a radioactive isotope initially has a mass of 6.88 kg.The half-life of this isotope is 1.34 h,and it decays by β^- emission.At the end of 2.68 h,what is the mass of this sphere?