Question 1

Gamma decay is important because

Accepted Answer

A) it enables us to measure nuclear energy levels. 
B) gamma-decay half-lives are usually short enough that we can neglect this radiation. 
C) analysis of gamma-ray spectra led to the Frank-Hertz experiment. 
D) it represents a reaction that does not satisfy all of the basic conservation principles. 
E) it is basically similar to the photoelectric effect. 
A) it enables us to measure nuclear energy levels. 
B) gamma-decay half-lives are usually short enough that we can neglect this radiation. 
C) analysis of gamma-ray spectra led to the Frank-Hertz experiment. 
D) it represents a reaction that does not satisfy all of the basic conservation principles. 
E) it is basically similar to the photoelectric effect.

Question 2

In what type of radioactive decay are the mass numbers of the parent and daughter nuclei different?

Accepted Answer

A) alpha 
B) beta 
C) gamma 
D) both alpha and beta 
E) both beta and gamma 
A) alpha 
B) beta 
C) gamma 
D) both alpha and beta 
E) both beta and gamma

Question 3

The control rods in a nuclear reactor are used to

Accepted Answer

A) produce neutrons. 
B) add fuel to the reactor. 
C) fragment elements by fission. 
D) absorb $\gamma$ rays. 
E) absorb neutrons. 
A) produce neutrons. 
B) add fuel to the reactor. 
C) fragment elements by fission. 
D) absorb $\gamma$ rays. 
E) absorb neutrons.

Question 4

A radioactive source has a half-life of 2 min.At time t = 0 it is placed near a detector and the counting rate is observed to be 3000 counts/s.The counting rate at t = 4 min will be

Accepted Answer

A) 1500 counts/s 
B) 750 counts/s 
C) 375 counts/s 
D) 188 counts/s 
E) 94 counts/s 
A) 1500 counts/s 
B) 750 counts/s 
C) 375 counts/s 
D) 188 counts/s 
E) 94 counts/s

Question 5

A particle is incident on a nucleus.The particle

Accepted Answer

A) can be scattered elastically by the nucleus. 
B) can be scattered inelastically by the nucleus with the nucleus in an excited state. 
C) can be absorbed by the nucleus completely. 
D) can be absorbed by the nucleus and other particle(s)emitted. 
E) All of the above are possible. 
A) can be scattered elastically by the nucleus. 
B) can be scattered inelastically by the nucleus with the nucleus in an excited state. 
C) can be absorbed by the nucleus completely. 
D) can be absorbed by the nucleus and other particle(s)emitted. 
E) All of the above are possible.

Question 6

The intensity of gamma rays passing through a material as a function of thickness,x is given by   where n is the number of atoms per cm3 and  $\sigma$ is the absorption cross section.If the intensity of gamma rays of a particular energy is reduced by half when they passed through 1 cm of lead,what is the absorption cross section for the gamma rays? The density of lead is 11.3 g/cm3 and its molar mass is 207 g.

Accepted Answer

A) 3.5 $\times$ 10-22 cm2 
B) 6.8 $\times$ 10 -22 cm2 
C) 4.6 $\times$ 10 -23 cm2 
D) 2.1 $\times$ 10  -23 cm2 
E) 8.4 $\times$ 10 -24 cm2 
A) 3.5 $\times$ 10-22 cm2 
B) 6.8 $\times$ 10 -22 cm2 
C) 4.6 $\times$ 10 -23 cm2 
D) 2.1 $\times$ 10  -23 cm2 
E) 8.4 $\times$ 10 -24 cm2

Question 7

A reactor that produces more fuel than it uses is called a

Accepted Answer

A) fission reactor. 
B) moderator reactor. 
C) breeder reactor. 
D) generating reactor. 
E) fusion reactor. 
A) fission reactor. 
B) moderator reactor. 
C) breeder reactor. 
D) generating reactor. 
E) fusion reactor.

Question 8

A cubical tray,one meter along the edge,contains 10,000 small hard spheres,each 0.0010 m in radius.Assume that no sphere is in front of another.If you shoot 108 small bullets (very small compared with the spheres)randomly into the broad face of the tray,the number of bullets that you can expect to be scattered by collisions with these spheres is

Accepted Answer

A) 104  
B) 106  
C) 107  
D) $\pi$ $\times$ 106  
E) 108  
A) 104  
B) 106  
C) 107  
D) $\pi$ $\times$ 106  
E) 108

Question 9

Which of the following radioactive decay products has the largest electric charge?

Accepted Answer

A) alpha particles 
B) beta particles 
C) gamma rays 
D) neutrons 
E) All of these have the same charge. 
A) alpha particles 
B) beta particles 
C) gamma rays 
D) neutrons 
E) All of these have the same charge.

Question 10

Uranium decomposes radioactively to form thorium (atomic number 90)by emitting an $\alpha$ particle from its nucleus.The force of repulsion between the thorium nucleus and the $\alpha$ particle when the distance between them is 9.0 fm is approximately

Accepted Answer

A) 7.2 fN 
B) 57 nN 
C) 4.6 pN 
D) 1.02 kN 
E) 0.51 kN 
A) 7.2 fN 
B) 57 nN 
C) 4.6 pN 
D) 1.02 kN 
E) 0.51 kN

Question 11

Initially a mixture of two radioactive sources contains the same number of nuclei of source A and source B.The half-life of A is 2 hours,and the half-life of B is 3 hours.What will be the ratio of remaining nuclei of A divided by remaining nuclei B after 12 hours? (Assume A does not decay into B or vice-versa.)

Accepted Answer

A) 0.250 
B) 0.125 
C) 0.5 
D) 0.0625 
E) None of these is correct. 
A) 0.250 
B) 0.125 
C) 0.5 
D) 0.0625 
E) None of these is correct.

Question 12

A 2000-year-old piece of dead wood gives 1400 counts per week in our detector system.How many counts per week would our system detect if the wood were living? (The half-life of 14C is 5730 years.)

Accepted Answer

A) 1520 counts per week 
B) 3200 counts per week 
C) 1270 counts per week 
D) 1780 counts per week 
E) 2130 counts per week 
A) 1520 counts per week 
B) 3200 counts per week 
C) 1270 counts per week 
D) 1780 counts per week 
E) 2130 counts per week

Question 13

A sample of   (which decays by $\beta$-emission)has an activity of 14.7 mCi.After 26.1 d it has an activity of 4.25 mCi.The half-life of 32P is approximately

Accepted Answer

A) 3.03 d 
B) 7.30 d 
C) 12.1 d 
D) 14.6 d 
E) 24.2 d 
A) 3.03 d 
B) 7.30 d 
C) 12.1 d 
D) 14.6 d 
E) 24.2 d

Question 14

Why is the ratio of neutrons to protons greater in the heavier elements?

Accepted Answer

A) The greater the number of protons,the weaker the proton-neutron strong nuclear force. 
B) The greater the number of neutrons,the weaker the proton-neutron strong nuclear force. 
C) The greater the number of protons,the greater the electrostatic force of repulsion. 
D) The greater the number of neutrons,the greater the electrostatic force of repulsion. 
E) There is actually a lesser ratio of neutrons to protons in the heavier elements. 
A) The greater the number of protons,the weaker the proton-neutron strong nuclear force. 
B) The greater the number of neutrons,the weaker the proton-neutron strong nuclear force. 
C) The greater the number of protons,the greater the electrostatic force of repulsion. 
D) The greater the number of neutrons,the greater the electrostatic force of repulsion. 
E) There is actually a lesser ratio of neutrons to protons in the heavier elements.

Question 15

A radiologist uses a radioactive isotope of iodine,123I,for thyroid scans.She receives a shipment of 15 mCi of this isotope at noon on Tuesday.The half-life of this isotope is 13.2 h.How much activity remains at noon on Thursday of the same week?

Accepted Answer

A) 12 mCi 
B) 1.2 mCi 
C) 2.4 mCi 
D) 4.2 mCi 
E) 24 mCi 
A) 12 mCi 
B) 1.2 mCi 
C) 2.4 mCi 
D) 4.2 mCi 
E) 24 mCi

Question 16

Calculate the Q-value for the following reaction,

Accepted Answer

The answer of Calculate the Q-value for the following reaction,...

Question 17

The subscript before the symbol for an element represents the number of

Accepted Answer

A) protons. 
B) neutrons. 
C) protons plus neutrons. 
D) protons minus neutrons. 
E) neutrons minus protons. 
A) protons. 
B) neutrons. 
C) protons plus neutrons. 
D) protons minus neutrons. 
E) neutrons minus protons.

Question 18

The "third-life," the time it takes nuclei to decay until one-third of the original amount remains,expressed in terms of the decay constant $\beta$,is

Accepted Answer

A) (ln 2)/3$\lambda$ 
B) (ln 3)/$\lambda$ 
C) (ln 0.333)/$\lambda$ 
D) 3(ln 2)/$\lambda$ 
E) $\lambda$/3 
A) (ln 2)/3$\lambda$ 
B) (ln 3)/$\lambda$ 
C) (ln 0.333)/$\lambda$ 
D) 3(ln 2)/$\lambda$ 
E) $\lambda$/3

Question 19

Fission occurs because the average binding energy per nucleon for the fission fragments is higher than that for the original nucleus.The change in binding energy per nucleon is approximately

Accepted Answer

A) 0.50 MeV 
B) 1.0 MeV 
C) 7.0 MeV 
D) 28 MeV 
E) 0.20 keV 
A) 0.50 MeV 
B) 1.0 MeV 
C) 7.0 MeV 
D) 28 MeV 
E) 0.20 keV

Question 20

The process of fission is easily understood in terms of

Accepted Answer

A) the shell model of the nucleus. 
B) the liquid-drop model of the nucleus. 
C) a quantum phenomenon known as the "tunnel effect." 
D) the Geiger-Nuttall rule. 
E) a radiative capture reaction involving a neutron. 
A) the shell model of the nucleus. 
B) the liquid-drop model of the nucleus. 
C) a quantum phenomenon known as the "tunnel effect." 
D) the Geiger-Nuttall rule. 
E) a radiative capture reaction involving a neutron.

Exam 40: Nuclear Physics

Gamma decay is important because

In what type of radioactive decay are the mass numbers of the parent and daughter nuclei different?

The control rods in a nuclear reactor are used to

A radioactive source has a half-life of 2 min.At time t = 0 it is placed near a detector and the counting rate is observed to be 3000 counts/s.The counting rate at t = 4 min will be

A particle is incident on a nucleus.The particle

A reactor that produces more fuel than it uses is called a

Which of the following radioactive decay products has the largest electric charge?

Uranium decomposes radioactively to form thorium (atomic number 90)by emitting an α\alphaα particle from its nucleus.The force of repulsion between the thorium nucleus and the α\alphaα particle when the distance between them is 9.0 fm is approximately

A 2000-year-old piece of dead wood gives 1400 counts per week in our detector system.How many counts per week would our system detect if the wood were living? (The half-life of 14C is 5730 years.)

A sample of (which decays by β\betaβ -emission)has an activity of 14.7 mCi.After 26.1 d it has an activity of 4.25 mCi.The half-life of 32P is approximately

Why is the ratio of neutrons to protons greater in the heavier elements?

A radiologist uses a radioactive isotope of iodine,123I,for thyroid scans.She receives a shipment of 15 mCi of this isotope at noon on Tuesday.The half-life of this isotope is 13.2 h.How much activity remains at noon on Thursday of the same week?

Calculate the Q-value for the following reaction,

The subscript before the symbol for an element represents the number of

The "third-life," the time it takes nuclei to decay until one-third of the original amount remains,expressed in terms of the decay constant β\betaβ ,is

Fission occurs because the average binding energy per nucleon for the fission fragments is higher than that for the original nucleus.The change in binding energy per nucleon is approximately

The process of fission is easily understood in terms of

Systems of Measurement

Motion in One Dimension

Motion in Two and Three Dimensions

Newtons Laws

Applications of Newtons Laws

Work and Energy

Conservation of Energy

Systems of Particles and Conservation of Linear Momentum

Rotation

Conservation of Angular Momentum

Gravity

Static Equilibrium and Elasticity

Fluids

Oscillations

Wave Motion

Superposition and Standing Waves

Temperature and the Kinetic Theory of Gases

Heat and the First Law of Thermodynamics

The Second Law of Thermodynamics

Thermal Properties and Processes

The Electric Field I: Discrete Charge Distributions

The Electric Field Ii: Continuous Charge Distributions

Electric Potential

Capacitance

Electric Current and Direct-Current Circuits

The Magnetic Field

Sources of the Magnetic Field

Magnetic Induction

Alternating-Current Circuits

Maxwells Equations and Electromagnetic Waves

Properties of Light

Optical Images

Interference and Diffraction

Wave Particle Duality and Quantum Physics

Applications of the Schrodinger Equation

Atoms

Molecules

Solids and the Theory of Conduction

Relativity

Elementary Particles and the Beginning of the Universe

Filters

Uranium decomposes radioactively to form thorium (atomic number 90)by emitting an $\alpha$ particle from its nucleus.The force of repulsion between the thorium nucleus and the $\alpha$ particle when the distance between them is 9.0 fm is approximately

A 2000-year-old piece of dead wood gives 1400 counts per week in our detector system.How many counts per week would our system detect if the wood were living? (The half-life of ¹⁴C is 5730 years.)

A radiologist uses a radioactive isotope of iodine,¹²³I,for thyroid scans.She receives a shipment of 15 mCi of this isotope at noon on Tuesday.The half-life of this isotope is 13.2 h.How much activity remains at noon on Thursday of the same week?

The "third-life," the time it takes nuclei to decay until one-third of the original amount remains,expressed in terms of the decay constant $\beta$ ,is