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

Question 2

The material used in certain nuclear bombs is 239Pu, which has a half-life of about 20,000 years. How long must we wait for a buried stockpile of this substance to decay to 4.0% of its original 239Pu mass?

Accepted Answer

A)  93,000 y 
B)  64,000 y 
C)  45,000 y 
D)  800 y 
A)  93,000 y 
B)  64,000 y 
C)  45,000 y 
D)  800 y

Question 3

In the nuclear reaction
n +   
U → X + 2e-
n is a neutron and e- is an electron, and the neutrinos have not been shown. Determine the atomic mass and atomic number of the missing nuclear product X, and write X in the standard form. It is NOT necessary to identify which atom X is.

Accepted Answer

The answer of In the nuclear reaction
n +  ...

Question 4

What mass of 14C (having a half-life of 5730 years) do you need to provide a decay rate of 280.0 Bq? (1 u = 1.6605 × 10-27 kg)

Accepted Answer

A)  1.70 × 10-12 kg 
B)  5.38 × 10-19 kg 
C)  3.84 × 10-20 kg 
D)  8.68 × 10-13 kg 
A)  1.70 × 10-12 kg 
B)  5.38 × 10-19 kg 
C)  3.84 × 10-20 kg 
D)  8.68 × 10-13 kg

Question 5

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 6

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 7

A stationary plutonium-239 nucleus decays into a uranium-235 nucleus plus an alpha particle. The energy released in the process is 5.24 MeV. Given the following mass values   He: 4.002603 u  
U: 235.043924 u
What is the kinetic energy of the  
U nucleus? (1 u =931.494 MeV/c2)

Accepted Answer

A)  0.0829 MeV 
B)  0.0837 MeV 
C)  0.0852 MeV 
D)  0.0863 MeV 
E)  0.0877 MeV 
A)  0.0829 MeV 
B)  0.0837 MeV 
C)  0.0852 MeV 
D)  0.0863 MeV 
E)  0.0877 MeV

Question 8

The radioactivity due to carbon-14 measured in a piece of a wood from an ancient site was found to produce 20 counts per minute from a given sample, whereas the same amount of carbon from a piece of living wood produced 160 counts per minute. The half-life of carbon-14, a beta emitter, is 5730 y. The age of the artifact is closest to

Accepted Answer

A)  5700 y 
B)  12,000 y 
C)  15,000 y 
D)  17,000 y 
E)  23,000 y 
A)  5700 y 
B)  12,000 y 
C)  15,000 y 
D)  17,000 y 
E)  23,000 y

Question 9

Living matter has 1.3 × 10-10 % of its carbon in the form of 14C which has a half-life of 5730 y. A mammoth bone has a 300-g sample of carbon separated from it, and the sample is found to have an activity of 20 decays per second. How old is the bone?

Accepted Answer

A)  15,000 y 
B)  10,900 y 
C)  11,500 y 
D)  7600 y 
E)  6400 y 
A)  15,000 y 
B)  10,900 y 
C)  11,500 y 
D)  7600 y 
E)  6400 y

Question 10

Heavier stable nuclei tend to have

Accepted Answer

A)  half as many protons as neutrons. 
B)  the same number of neutrons and protons. 
C)  more neutrons than protons. 
D)  no clear trend in the relative number of neutrons and protons. 
E)  more protons than neutrons. 
A)  half as many protons as neutrons. 
B)  the same number of neutrons and protons. 
C)  more neutrons than protons. 
D)  no clear trend in the relative number of neutrons and protons. 
E)  more protons than neutrons.

Question 11

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 12

Find the reaction energy (Q value) of the reaction   N +  
He →  
O +  
H, given the following masses:  
N: 14.003074 u  
He: 4.002603 u  
O : 16.999131 u  
H: 1.007825 u
(1 u = 931.5 MeV/c2)

Accepted Answer

A)  -1.191 MeV 
B)  -2.030 MeV 
C)  -3.241 MeV 
D)  -6.724 MeV 
E)  -9.055 MeV 
A)  -1.191 MeV 
B)  -2.030 MeV 
C)  -3.241 MeV 
D)  -6.724 MeV 
E)  -9.055 MeV

Question 13

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

Question 14

Fermium-253 has a half-life of 3.00 d. A sample of fermium contains 7.37 × 107 nuclei. How long will it take for there to be only 3.36 × 106 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 15

A hospital patient has been given some 131I (half-life = 8.04 d) which decays at 4.2 times the acceptable level for exposure to the general public. How long must the patient wait for the decay rate to reach the acceptable level? Assume that the material merely decays and is not excreted by the body.

Accepted Answer

A)  17 d 
B)  12 d 
C)  8.0 d 
D)  7.2 d 
A)  17 d 
B)  12 d 
C)  8.0 d 
D)  7.2 d

Question 16

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 17

The stability of   C 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  
Be: 7.016928 u  
B: 11.009305 u  
C: 11.011433 u  
N: 11.026742 u
The  
C 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 18

In massive stars, three helium nuclei fuse together, forming a carbon nucleus. This reaction heats the core of the star. The net mass of the three helium nuclei must therefore be

Accepted Answer

A)  higher than that of the carbon nucleus. 
B)  less than that of the carbon nucleus. 
C)  the same as that of the carbon nucleus since mass is always conserved. 
D)  the same as that of the carbon nucleus since energy is always conserved. 
A)  higher than that of the carbon nucleus. 
B)  less than that of the carbon nucleus. 
C)  the same as that of the carbon nucleus since mass is always conserved. 
D)  the same as that of the carbon nucleus since energy is always conserved.

Question 19

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 20

Consider two different isotopes of the same neutral element. Which statements about these isotopes are true? (There may be more than one correct choice.)

Accepted Answer

A)  Both isotopes contain the same number of neutrons. 
B)  Both isotopes contain the same number of protons. 
C)  Both isotopes contain the same number of nucleons. 
D)  Both isotopes contain the same number of orbital electrons. 
E)  The sum of the protons and neutrons is the same for both isotopes. 
A)  Both isotopes contain the same number of neutrons. 
B)  Both isotopes contain the same number of protons. 
C)  Both isotopes contain the same number of nucleons. 
D)  Both isotopes contain the same number of orbital electrons. 
E)  The sum of the protons and neutrons is the same for both isotopes.

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?

The material used in certain nuclear bombs is 239Pu, which has a half-life of about 20,000 years. How long must we wait for a buried stockpile of this substance to decay to 4.0% of its original 239Pu mass?

In the nuclear reaction n + U → X + 2e- n is a neutron and e- is an electron, and the neutrinos have not been shown. Determine the atomic mass and atomic number of the missing nuclear product X, and write X in the standard form. It is NOT necessary to identify which atom X is.

What mass of 14C (having a half-life of 5730 years) do you need to provide a decay rate of 280.0 Bq? (1 u = 1.6605 × 10-27 kg)

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)

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.

A stationary plutonium-239 nucleus decays into a uranium-235 nucleus plus an alpha particle. The energy released in the process is 5.24 MeV. Given the following mass values He: 4.002603 u U: 235.043924 u What is the kinetic energy of the U nucleus? (1 u =931.494 MeV/c2)

Living matter has 1.3 × 10-10 % of its carbon in the form of 14C which has a half-life of 5730 y. A mammoth bone has a 300-g sample of carbon separated from it, and the sample is found to have an activity of 20 decays per second. How old is the bone?

Heavier stable nuclei tend to have

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

Find the reaction energy (Q value) of the reaction N + He → O + H, given the following masses: N: 14.003074 u He: 4.002603 u O : 16.999131 u H: 1.007825 u (1 u = 931.5 MeV/c2)

Fermium-253 has a half-life of 3.00 d. A sample of fermium contains 7.37 × 107 nuclei. How long will it take for there to be only 3.36 × 106 fermium nuclei in this sample?

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.

The stability of C 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 Be: 7.016928 u B: 11.009305 u C: 11.011433 u N: 11.026742 u The C nuclide is

In massive stars, three helium nuclei fuse together, forming a carbon nucleus. This reaction heats the core of the star. The net mass of the three helium nuclei must therefore be

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 two different isotopes of the same neutral element. Which statements about these isotopes are true? (There may be more than one correct choice.)

Units, Physical Quantities, and Vectors

Motion Along a Straight Line

Motion in Two or Three Dimensions

Newtons Laws of Motion

Applying Newtons Laws

Work and Kinetic Energy

Potential Energy and Energy Conservation

Momentum, Impulse, and Collisions

Rotation of Rigid Bodies

Equilibrium and Elasticity

Fluid Mechanics

Gravitation

Periodic Motion

Mechanical Waves

Sound and Hearing

Temperature and Heat

Thermal Properties of Matter

The First Law of Thermodynamics

The Second Law of Thermodynamics

Electric Charge and Electric Field

Gausss Law

Electric Potential

Capacitance and Dielectrics

Current, Resistance, and Electromotive Force

Direct-Current Circuits

Magnetic Field and Magnetic Forces

Sources of Magnetic Field

Electromagnetic Induction

Inductance

Alternating Current

Electromagnetic Waves

The Nature and Propagation of Light

Geometric Optics

Interference

Diffraction

Relativity

Photons: Light Waves Behaving As Particles

Particles Behaving As Waves

Quantum Mechanics

Atomic Structure

Molecules and Condensed Matter

Particle Physics and Cosmology

Filters

The material used in certain nuclear bombs is ²³⁹Pu, which has a half-life of about 20,000 years. How long must we wait for a buried stockpile of this substance to decay to 4.0% of its original ²³⁹Pu mass?

What mass of ¹⁴C (having a half-life of 5730 years) do you need to provide a decay rate of 280.0 Bq? (1 u = 1.6605 × 10^-27 kg)

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)

A stationary plutonium-239 nucleus decays into a uranium-235 nucleus plus an alpha particle. The energy released in the process is 5.24 MeV. Given the following mass values He: 4.002603 u U: 235.043924 u What is the kinetic energy of the U nucleus? (1 u =931.494 MeV/c²)

Living matter has 1.3 × 10^-10 % of its carbon in the form of ¹⁴C which has a half-life of 5730 y. A mammoth bone has a 300-g sample of carbon separated from it, and the sample is found to have an activity of 20 decays per second. How old is the bone?

Find the reaction energy (Q value) of the reaction N + He → O + H, given the following masses: N: 14.003074 u He: 4.002603 u O : 16.999131 u H: 1.007825 u (1 u = 931.5 MeV/c²)

Fermium-253 has a half-life of 3.00 d. A sample of fermium contains 7.37 × 10⁷nuclei. How long will it take for there to be only 3.36 × 10⁶ fermium nuclei in this sample?

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.

The stability of C 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 Be: 7.016928 u B: 11.009305 u C: 11.011433 u N: 11.026742 u The C 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