Question 1

The energy at which the  endothermic reaction takes place is

Accepted Answer

A)  1.19 MeV 
B)  0.925 MeV 
C)  1.52 MeV 
D)  1.28 MeV 
E)  9.25 MeV

Question 2

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. If the detection efficiency is 25%, how many radioactive nuclei are there at time t = 2 min?

Accepted Answer

A)  1.04 * 106  
B)  1.67 * 106  
C)  2.08 *106  
D)  3.41 * 106  
E)  3.79 * 106

Question 3

After a star fuses most its hydrogen into helium, it begins to fuse the helium into carbon. The energy released in fusing helium nuclei ($\alpha$particles) into carbon is approximately

Accepted Answer

A)  0.730 MeV 
B)  1.46 MeV 
C)  7.30 MeV 
D)  14.6 MeV 
E)  73.0 MeV

Question 4

In the decay scheme  the blanks should contain

Accepted Answer

A)  $\beta$+ and n 
B)  $\beta$- and $\rho$ 
C)  $\beta$- and p 
D)  $\beta$+ and $\nu$ 
E)  $\beta$+ and $\beta$-

Question 5

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)   $\pi$*106  
E)  108

Question 6

Many elements show resonances in neutron capture. What are these resonances?

Accepted Answer

A)  especially large Q values for each neutron capture 
B)  certain incident energies at which neutrons are most readily captured 
C)  especially large N values resulting from the capture of many neutrons 
D)  certain incident energies at which neutrons are least readily captured 
E)  certain incident angles at which neutrons are most readily captured

Question 7

Although the neutron-capture cross section curve is generally proportional to 1/v, where v is the velocity of the incident neutrons, it has several pronounced peaks. These peaks are an indication of

Accepted Answer

A)  resonances with nuclear energy levels. 
B)  characteristic $\gamma$ rays from the nucleus. 
C)  barrier penetration. 
D)  $\alpha$ particle emission. 
E)  characteristic X rays.

Question 8

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.

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.

Question 10

The nuclear reaction process in which a heavy nucleus splits into two roughly equal parts is known as

Accepted Answer

A)  fission 
B)  fusion 
C)  spallation 
D)  isomerism 
E)  internal conversion

Question 11

A radioactive nucleus with Z = 92 and A = 235 decays through a series of alpha, beta, and gamma emissions to a stable nucleus with Z = 82 and A = 207. The number of alpha particles and the number of beta particles emitted during the entire process are

Accepted Answer

A)  8 alpha particles and 6 beta particles. 
B)  7 alpha particles and 4 beta particles. 
C)  7 alpha particles and 10 beta particles. 
D)  14 alpha particles and 7 beta particles. 
E)  None of these is correct.

Question 12

What is the available energy EA for the  reaction if the kinetic energy of the proton is 10.0 MeV?

Accepted Answer

A)  10.0 MeV 
B)  11.4 MeV 
C)  8.75 MeV 
D)  27.3 MeV 
E)  5.00 MeV

Question 13

Atoms of an element that have different atomic masses are called

Accepted Answer

A)  ions 
B)  isobars 
C)  isotopes 
D)  metastable 
E)  dielectrics

Question 14

The element that would best serve as a control rod in a nuclear reactor is

Accepted Answer

The answer of The element that would best serve as...

Question 15

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.

Question 16

Curve 2 is the binding energy per nucleon as a function of the mass number A. The other curves represent the contributions of various forms of energy that contribute to the binding energy. The curve that best represents the contribution of the Coulomb force is

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 17

The graph that represents the interaction of the proton and neutron is

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 18

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

Question 19

If, on the average, each fission reaction of 235U releases 200 MeV of energy, how many nuclei of 235U fission every second in a 200-MW reactor?

Accepted Answer

A)  6.3 *1018  
B)  6.0 * 1023  
C)  1.0 * 1019  
D)  1.6 * 1019  
E)  2.7 * 1018

Question 20

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. It is observed that the intensity of gamma rays of a particular energy is reduced by half when they passed through 1 cm of lead. What is the thickness of lead needed to reduce the intensity to a quarter?

Accepted Answer

A)  1.0 cm 
B)  1.5 cm 
C)  2.0 cm 
D)  3.0 cm 
E)  4.0 cm

Exam 20: Nuclear Physics

The energy at which the endothermic reaction takes place is

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. If the detection efficiency is 25%, how many radioactive nuclei are there at time t = 2 min?

In the decay scheme $In the decay scheme the blanks should contain A) \beta <sup>+</sup> and n B) \beta <sup>-</sup> and \rho C) \beta <sup>-</sup> and p D) \beta <sup>+</sup> and \nu E) \beta <sup>+</sup> and \beta <sup>- </sup>$ the blanks should contain

Many elements show resonances in neutron capture. What are these resonances?

Gamma decay is important because

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

The nuclear reaction process in which a heavy nucleus splits into two roughly equal parts is known as

A radioactive nucleus with Z = 92 and A = 235 decays through a series of alpha, beta, and gamma emissions to a stable nucleus with Z = 82 and A = 207. The number of alpha particles and the number of beta particles emitted during the entire process are

What is the available energy E_A for the reaction if the kinetic energy of the proton is 10.0 MeV?

Atoms of an element that have different atomic masses are called

The element that would best serve as a control rod in a nuclear reactor is

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

Curve 2 is the binding energy per nucleon as a function of the mass number A. The other curves represent the contributions of various forms of energy that contribute to the binding energy. The curve that best represents the contribution of the Coulomb force is

The graph that represents the interaction of the proton and neutron is

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

If, on the average, each fission reaction of ²³⁵U releases 200 MeV of energy, how many nuclei of ²³⁵U fission every second in a 200-MW reactor?

Exam 20: Nuclear Physics

The energy at which the endothermic reaction takes place is

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. If the detection efficiency is 25%, how many radioactive nuclei are there at time t = 2 min?

After a star fuses most its hydrogen into helium, it begins to fuse the helium into carbon. The energy released in fusing helium nuclei ( α\alphaα particles) into carbon is approximately

In the decay scheme the blanks should contain

Many elements show resonances in neutron capture. What are these resonances?

Although the neutron-capture cross section curve is generally proportional to 1/v, where v is the velocity of the incident neutrons, it has several pronounced peaks. These peaks are an indication of

Gamma decay is important because

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

The nuclear reaction process in which a heavy nucleus splits into two roughly equal parts is known as

A radioactive nucleus with Z = 92 and A = 235 decays through a series of alpha, beta, and gamma emissions to a stable nucleus with Z = 82 and A = 207. The number of alpha particles and the number of beta particles emitted during the entire process are

What is the available energy EA for the reaction if the kinetic energy of the proton is 10.0 MeV?

Atoms of an element that have different atomic masses are called

The element that would best serve as a control rod in a nuclear reactor is

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

Curve 2 is the binding energy per nucleon as a function of the mass number A. The other curves represent the contributions of various forms of energy that contribute to the binding energy. The curve that best represents the contribution of the Coulomb force is

The graph that represents the interaction of the proton and neutron is

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

If, on the average, each fission reaction of 235U releases 200 MeV of energy, how many nuclei of 235U fission every second in a 200-MW reactor?

In the decay scheme $In the decay scheme the blanks should contain A) \beta <sup>+</sup> and n B) \beta <sup>-</sup> and \rho C) \beta <sup>-</sup> and p D) \beta <sup>+</sup> and \nu E) \beta <sup>+</sup> and \beta <sup>- </sup>$ the blanks should contain

What is the available energy E_A for the reaction if the kinetic energy of the proton is 10.0 MeV?

If, on the average, each fission reaction of ²³⁵U releases 200 MeV of energy, how many nuclei of ²³⁵U fission every second in a 200-MW reactor?