Question 1

Particles composed of quarks are

Accepted Answer

A)  photons. 
B)  leptons. 
C)  neutrinos. 
D)  W and Z bosons. 
E)  baryons and mesons. 
A)  photons. 
B)  leptons. 
C)  neutrinos. 
D)  W and Z bosons. 
E)  baryons and mesons. E

Question 2

Which of the following reactions violates conservation of strangeness?

Accepted Answer

A)  Ω− → 3γ 
B) 
  
C) 
  
D) 
  
E) 
  
A)  Ω− → 3γ 
B) 
  
C) 
  
D) 
  
E) 
  A

Question 3

All particles can be classified into

Accepted Answer

A)  Leptons and quarks 
B)  Hadrons and leptons 
C)  Baryons and leptons 
D)  Mesons and Baryons 
A)  Leptons and quarks 
B)  Hadrons and leptons 
C)  Baryons and leptons 
D)  Mesons and Baryons B

Question 4

A K0 particle at rest decays into a π+ and a π−. What will be the speed of each of the pions? The mass of the K0 is 497.7 MeV/c2 and the mass of each π is 139.6 MeV/c2.

Accepted Answer

Question 5

The particle Δ++ has an electric charge twice that of the proton and baryon number +1. Strangeness, charm, bottomness and topness are all 0. Its quark composition must be

Accepted Answer

A)  uuu. 
B)  uud. 
C)  udd. 
D) 
  . 
E) 
  . 
A)  uuu. 
B)  uud. 
C)  udd. 
D) 
  . 
E) 
  .

Question 6

Name at least one conservation law that prevents each of the following reactions:
a)
π− + p → Σ+ + π°
b)
p → π+ + π+ + π−

Accepted Answer

a) charge,

Question 7

The following reaction can occur by the strong interaction: π0 + n → K+ + Σ−. If the quark composition of the n is (udd), the π° is (   ), and the composition of the K+ is (   ), find the quark composition of the Σ−.

Accepted Answer

A)  sss 
B)  uds 
C)  dds 
D) 
  
E) 
  
A)  sss 
B)  uds 
C)  dds 
D) 
  
E)

Question 8

According to the Hubble law, where H = 17 km/s/106 lightyears, what is the velocity of recession of a quasar at a distance of 2 billion lightyears from Earth?

Accepted Answer

A)  0.75 c 
B)  0.33 c 
C)  0.55 c 
D)  0.11 c 
E)  0.93 c 
A)  0.75 c 
B)  0.33 c 
C)  0.55 c 
D)  0.11 c 
E)  0.93 c

Question 9

The particle reaction   cannot occur because

Accepted Answer

A)  electric charge is not conserved. 
B)  strangeness is not conserved. 
C)  baryon number is not conserved. 
D)  all of the above are not conserved. 
E)  both (a) and (b) above are not conserved. 
A)  electric charge is not conserved. 
B)  strangeness is not conserved. 
C)  baryon number is not conserved. 
D)  all of the above are not conserved. 
E)  both (a) and (b) above are not conserved.

Question 10

Which of the following decays violates conservation of lepton number?

Accepted Answer

A) 
  
B) 
  
C) 
  
D) 
  
E) 
  
A) 
  
B) 
  
C) 
  
D) 
  
E)

Question 11

The decay   is not possible because

Accepted Answer

A)  Le is not conserved. 
B)  Lμ is not conserved. 
C)  quark number is not conserved. 
D)  all of the above are not conserved. 
E)  only Le and Lμ are not conserved. 
A)  Le is not conserved. 
B)  Lμ is not conserved. 
C)  quark number is not conserved. 
D)  all of the above are not conserved. 
E)  only Le and Lμ are not conserved.

Question 12

If a K0 meson at rest decays in 0.89 × 10−10 s, how far will a K0 meson moving at 0.96 c travel through a bubble chamber?

Accepted Answer

A)  17 cm 
B)  1.1 cm 
C)  53 cm 
D)  42 mm 
E)  9.2 cm 
A)  17 cm 
B)  1.1 cm 
C)  53 cm 
D)  42 mm 
E)  9.2 cm

Question 13

Which one of the following is not true of neutrinos?

Accepted Answer

A)  They have no charge. 
B)  They have no spin. 
C)  One type of neutrino may change into another type of neutrino. 
D)  They are leptons. 
E)  They do not take part in strong nuclear interactions. 
A)  They have no charge. 
B)  They have no spin. 
C)  One type of neutrino may change into another type of neutrino. 
D)  They are leptons. 
E)  They do not take part in strong nuclear interactions.

Question 14

If the quark content of the proton, p, is uud, the quark content of the antiproton,   is

Accepted Answer

A)  uud. 
B)  udd. 
C) 
  . 
D) 
  . 
E) 
  . 
A)  uud. 
B)  udd. 
C) 
  . 
D) 
  . 
E) 
  .

Question 15

Of the following leptons, which has the greatest rest energy?

Accepted Answer

A) 
  
B) 
  
C) 
  
D) 
  
E) 
  
A) 
  
B) 
  
C) 
  
D) 
  
E)

Question 16

The rest-energy of the Z0 boson is 96 GeV. Using this information, find the maximum length of time a virtual Z0 can exist, in accordance with the uncertainty principle   . (1 eV = 1.6 × 10−19 J.)

Accepted Answer

A)  3.4 × 10−27 s 
B)  7.5 × 10−30 s 
C)  2.4 × 10−24 s 
D)  1.9 × 10−21 s 
E)  6.3 × 10−5 s 
A)  3.4 × 10−27 s 
B)  7.5 × 10−30 s 
C)  2.4 × 10−24 s 
D)  1.9 × 10−21 s 
E)  6.3 × 10−5 s

Question 17

Calculate the range of the force that might be produced by the virtual exchange of a proton. (mp = 1.67 × 10−27 kg, h = 6.626 × 10−34 J ⋅ s)

Accepted Answer

Question 18

The minimum energy needed to produce a positron is

Accepted Answer

A)  3 MeV 
B)  2 MeV 
C)  1 MeV 
D)  4 MeV 
E)  0.51 MeV 
A)  3 MeV 
B)  2 MeV 
C)  1 MeV 
D)  4 MeV 
E)  0.51 MeV

Question 19

A Σ+ particle, composed of uus quarks, has the same ____ as a proton.

Accepted Answer

A)  baryon number and charm. 
B)  baryon number and electric charge. 
C)  baryon number and strangeness. 
D)  baryon number, electric charge, and charm. 
E)  electric charge and strangeness. 
A)  baryon number and charm. 
B)  baryon number and electric charge. 
C)  baryon number and strangeness. 
D)  baryon number, electric charge, and charm. 
E)  electric charge and strangeness.

Question 20

A model for how repulsive forces between two particles can be mediated by a third particle would be

Accepted Answer

A)  A person on a skateboard pushing against a wall. 
B)  two people in two canoes throwing a ball back and forth. 
C)  two people in two canoes each pulling on one end of a rope. 
D)  two people in two skateboards giving each other a shove. 
E)  two people in two skateboards each pulling on one end of a rope. 
A)  A person on a skateboard pushing against a wall. 
B)  two people in two canoes throwing a ball back and forth. 
C)  two people in two canoes each pulling on one end of a rope. 
D)  two people in two skateboards giving each other a shove. 
E)  two people in two skateboards each pulling on one end of a rope.

Exam 46: Particle Physics and Cosmology

Particles composed of quarks are

Which of the following reactions violates conservation of strangeness?

All particles can be classified into

A K0 particle at rest decays into a π+ and a π−. What will be the speed of each of the pions? The mass of the K0 is 497.7 MeV/c2 and the mass of each π is 139.6 MeV/c2.

The particle Δ++ has an electric charge twice that of the proton and baryon number +1. Strangeness, charm, bottomness and topness are all 0. Its quark composition must be

Name at least one conservation law that prevents each of the following reactions: a) π− + p → Σ+ + π° b) p → π+ + π+ + π−

The following reaction can occur by the strong interaction: π0 + n → K+ + Σ−. If the quark composition of the n is (udd), the π° is ( ), and the composition of the K+ is ( ), find the quark composition of the Σ−.

According to the Hubble law, where H = 17 km/s/106 lightyears, what is the velocity of recession of a quasar at a distance of 2 billion lightyears from Earth?

The particle reaction cannot occur because

Which of the following decays violates conservation of lepton number?

The decay is not possible because

If a K0 meson at rest decays in 0.89 × 10−10 s, how far will a K0 meson moving at 0.96 c travel through a bubble chamber?

Which one of the following is not true of neutrinos?

If the quark content of the proton, p, is uud, the quark content of the antiproton, is

Of the following leptons, which has the greatest rest energy?

The rest-energy of the Z0 boson is 96 GeV. Using this information, find the maximum length of time a virtual Z0 can exist, in accordance with the uncertainty principle . (1 eV = 1.6 × 10−19 J.)

Calculate the range of the force that might be produced by the virtual exchange of a proton. (mp = 1.67 × 10−27 kg, h = 6.626 × 10−34 J ⋅ s)

The minimum energy needed to produce a positron is

A Σ+ particle, composed of uus quarks, has the same ____ as a proton.

A model for how repulsive forces between two particles can be mediated by a third particle would be

Physics and Measurement

Motion in One Dimension

Vectors

Motion in Two Dimensions

The Laws of Motion

Circular Motion and Other Applications of Newtons Laws

Energy of a System

Conservation of Energy

Linear Momentum and Collisions

Rotation of a Rigid Object About a Fixed Axis

Angular Momentum

Static Equilibrium and Elasticity

Universal Gravitation

Fluid Mechanics

Oscillatory Motion

Wave Motion

Superposition and Standing Waves

Temperature

The First Law of Thermodynamics

The Kinetic Theory of Gases

Heat Engines, Entropy, and the Second Law of Thermodynamics

Electric Fields

Gausss Law

Electric Potential

Capacitance and Dielectrics

Current and Resistance

Direct-Current Circuits

Magnetic Fields

Sources of the Magnetic Field

Faradays Law

Inductance

Alternating-Current Circuits

Electromagnetic Waves

The Nature of Light and the Principles of Ray Optics

Image Formation

Wave Optics

Diffraction Patterns and Polarization

Relativity

Introduction to Quantum Physics

Quantum Mechanics

Atomic Physics

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A K⁰ particle at rest decays into a π⁺ and a π⁻. What will be the speed of each of the pions? The mass of the K⁰ is 497.7 MeV/c² and the mass of each π is 139.6 MeV/c².

The particle Δ⁺⁺ has an electric charge twice that of the proton and baryon number +1. Strangeness, charm, bottomness and topness are all 0. Its quark composition must be

Name at least one conservation law that prevents each of the following reactions: a) π⁻ + p → Σ⁺ + π° b) p → π⁺ + π⁺ + π⁻

The following reaction can occur by the strong interaction: π⁰ + n → K⁺ + Σ⁻. If the quark composition of the n is (udd), the π° is ( ), and the composition of the K⁺ is ( ), find the quark composition of the Σ⁻.

According to the Hubble law, where H = 17 km/s/10⁶ lightyears, what is the velocity of recession of a quasar at a distance of 2 billion lightyears from Earth?

If a K⁰ meson at rest decays in 0.89 × 10−¹⁰ s, how far will a K⁰ meson moving at 0.96 c travel through a bubble chamber?

The rest-energy of the Z⁰ boson is 96 GeV. Using this information, find the maximum length of time a virtual Z⁰ can exist, in accordance with the uncertainty principle . (1 eV = 1.6 × 10−¹⁹ J.)

Calculate the range of the force that might be produced by the virtual exchange of a proton. (m_p = 1.67 × 10−²⁷ kg, h = 6.626 × 10−³⁴ J ⋅ s)

A Σ⁺ particle, composed of uus quarks, has the same ____ as a proton.