Question 1

The cosmic background radiation strongly suggests that

Accepted Answer

A)  the energy radiated from the quasars is redshifted. 
B)  the universe has always been as it is today. 
C)  the universe evolved from a cold, rarified state. 
D)  the universe evolved from a hot, uniform state. 
E)  matter is continuously being created. 
A)  the energy radiated from the quasars is redshifted. 
B)  the universe has always been as it is today. 
C)  the universe evolved from a cold, rarified state. 
D)  the universe evolved from a hot, uniform state. 
E)  matter is continuously being created.

Question 2

The Starship Enterprise is powered by combining matter with antimatter. Suppose 1 kg of each are combined and ejected backward at the speed of light, what is the final speed of the Enterprise starting from rest? Assume that the mass of the Enterprise is 10,000 kg and the spaceship does not reach relativistic speed.

Accepted Answer

A)  c/100 
B)  c/500 
C)  c/2000 
D)  c/5000 
E)  c/10000 
A)  c/100 
B)  c/500 
C)  c/2000 
D)  c/5000 
E)  c/10000

Question 3

The charge of the particle dds is

Accepted Answer

A)  e. 
B)  1/3)e. 
C)  -2/3)e. 
D)  -e. 
E)  zero. 
A)  e. 
B)  1/3)e. 
C)  -2/3)e. 
D)  -e. 
E)  zero.

Question 4

Which of the following are possible combinations of quarks?
 1)   2)   3)   4)   5)   6)

Accepted Answer

A)  1,2,3,5,6 
B)  1,3,5,6 
C)  2,3,5,6 
D)  1,3,4,5 
E)  1,3,4,5,6 
A)  1,2,3,5,6 
B)  1,3,5,6 
C)  2,3,5,6 
D)  1,3,4,5 
E)  1,3,4,5,6

Question 5

Assuming a radial speed of a galaxy to be 100 km/s from us and Hubble's constant to be 23 km/s/106 c · y, how far is the galaxy from us?

Accepted Answer

A)  2300 ly 
B)  2300 Mly 
C)  4.3 Mly 
D)  0.23 Mly 
E)  None of these is correct. 
A)  2300 ly 
B)  2300 Mly 
C)  4.3 Mly 
D)  0.23 Mly 
E)  None of these is correct.

Question 6

Which of the following choices lists the four known types of forces in nature in order of decreasing strength?

Accepted Answer

A)  strong nuclear, electromagnetic, weak nuclear, gravitational 
B)  electromagnetic, strong nuclear, weak nuclear, gravitational 
C)  strong nuclear, gravitational, weak nuclear, electromagnetic 
D)  strong nuclear, weak nuclear, electromagnetic, gravitational 
E)  strong nuclear, electromagnetic, gravitational, weak nuclear 
A)  strong nuclear, electromagnetic, weak nuclear, gravitational 
B)  electromagnetic, strong nuclear, weak nuclear, gravitational 
C)  strong nuclear, gravitational, weak nuclear, electromagnetic 
D)  strong nuclear, weak nuclear, electromagnetic, gravitational 
E)  strong nuclear, electromagnetic, gravitational, weak nuclear

Question 7

The charge of the d quark is

Accepted Answer

A)  e. 
B)  -1/3)e. 
C)  2/3)e. 
D)  -2/3)e. 
E)  1/3)e. 
A)  e. 
B)  -1/3)e. 
C)  2/3)e. 
D)  -2/3)e. 
E)  1/3)e.

Question 8

In the standard model,

Accepted Answer

A)  the fundamental particles are the leptons and quarks. 
B)  the force carriers are the photon, the W±, the Z particles, and the gluons. 
C)  every force in nature is due to the strong, electromagnetic, weak, or gravitational force. 
D)  a particle experiences one of the basic interactions if it carries a charge associated with that interaction. 
E)  All of these are correct. 
A)  the fundamental particles are the leptons and quarks. 
B)  the force carriers are the photon, the W±, the Z particles, and the gluons. 
C)  every force in nature is due to the strong, electromagnetic, weak, or gravitational force. 
D)  a particle experiences one of the basic interactions if it carries a charge associated with that interaction. 
E)  All of these are correct.

Question 9

A classical calculation shows that the critical mass density of the universe is given by   where H is the Hubble constant and G is the gravitation constant. If the density is below this value, the universe will expand forever, whereas if it is above this value the universe will eventually stop expanding and collapse. Approximately how many hydrogen atoms per m3 is the critical density equivalent to?

Accepted Answer

A)  4 
B)  40 
C)  400 
D)  4000 
E)  40,000 
A)  4 
B)  40 
C)  400 
D)  4000 
E)  40,000

Question 10

Virtual photons are particles that mediate the Coulomb force and travel at the speed of light. What is the approximate energy of the virtual photons that mediate between the ground state electron and the proton in a hydrogen atom? The radius of the electron in the ground state is 0.053 nm.

Accepted Answer

A)  100 eV 
B)  500 eV 
C)  1000 eV 
D)  4 keV 
E)  0.5 MeV 
A)  100 eV 
B)  500 eV 
C)  1000 eV 
D)  4 keV 
E)  0.5 MeV

Question 11

The cosmic background radiation is an important aspect of the Big Bang theory because it

Accepted Answer

A)  shows that evolutionary models of the universe are incorrect. 
B)  does not show any redshift. 
C)  could not be produced in the universe as it is now, which suggests that conditions must have been different in the past. 
D)  discredits Hubble's law. 
E)  is useful in identifying the locations of important objects in the universe. 
A)  shows that evolutionary models of the universe are incorrect. 
B)  does not show any redshift. 
C)  could not be produced in the universe as it is now, which suggests that conditions must have been different in the past. 
D)  discredits Hubble's law. 
E)  is useful in identifying the locations of important objects in the universe.

Question 12

The conservation law violated by the reaction p → π0 + e+ is the conservation of

Accepted Answer

A)  charge. 
B)  energy. 
C)  linear momentum. 
D)  lepton number and baryon number. 
E)  angular momentum. 
A)  charge. 
B)  energy. 
C)  linear momentum. 
D)  lepton number and baryon number. 
E)  angular momentum.

Question 13

A particle and its antiparticle must have

Accepted Answer

A)  opposite spins. 
B)  opposite charges. 
C)  opposite masses. 
D)  opposite forces. 
E)  both opposite spins and opposite charges. 
A)  opposite spins. 
B)  opposite charges. 
C)  opposite masses. 
D)  opposite forces. 
E)  both opposite spins and opposite charges.

Question 14

Redshift measurements of a galaxy yield a recession speed of 1700 km/s. Hubble's constant H is 23-km/s/106 ly. The distance to the galaxy is approximately

Accepted Answer

A)  36 × 106 ly. 
B)  47 × 106 ly. 
C)  53 × 106 ly. 
D)  66 × 106 ly. 
E)  74 × 106 ly. 
A)  36 × 106 ly. 
B)  47 × 106 ly. 
C)  53 × 106 ly. 
D)  66 × 106 ly. 
E)  74 × 106 ly.

Question 15

The charge of the particle   is

Accepted Answer

A)  e. 
B)  1/3)e. 
C)  -2/3)e. 
D)  -e. 
E)  2e. 
A)  e. 
B)  1/3)e. 
C)  -2/3)e. 
D)  -e. 
E)  2e.

Question 16

The reaction e+ + e- →

Accepted Answer

A)  describes the annihilation of a positron and an electron. 
B)  has a large probability of occurrence only if the positron is at rest or nearly at rest. 
C)  requires two photons moving in opposite directions to conserve linear momentum. 
D)  conserves the electron lepton number. 
E)  All of these are correct. 
A)  describes the annihilation of a positron and an electron. 
B)  has a large probability of occurrence only if the positron is at rest or nearly at rest. 
C)  requires two photons moving in opposite directions to conserve linear momentum. 
D)  conserves the electron lepton number. 
E)  All of these are correct.

Question 17

The Coulomb force in the classical sense is understood in terms of electric fields. However, in quantum mechanics, the Coulomb force is described in terms of exchange of virtual photons between the charged particles. Why doesn't the creation of the virtual photons violate the principle of conservation of energy?

Accepted Answer

A)  This is because in quantum mechanics energy is not conserved. 
B)  The uncertainty principle,   , allows photons to be created provided they are absorbed within the time interval Δt. 
C)  The photons do not have any energy since they are massless. 
D)  The virtual photons are not real photons and hence do not carry any energy. 
E)  None of these is correct. 
A)  This is because in quantum mechanics energy is not conserved. 
B)  The uncertainty principle,   , allows photons to be created provided they are absorbed within the time interval Δt. 
C)  The photons do not have any energy since they are massless. 
D)  The virtual photons are not real photons and hence do not carry any energy. 
E)  None of these is correct.

Question 18

Forces between electrons or positrons and nucleons that result in beta decay are best understood in terms of

Accepted Answer

A)  the strong nuclear interaction. 
B)  the electromagnetic interaction. 
C)  the weak nuclear interaction. 
D)  the gravitational interaction. 
E)  None of these is correct. 
A)  the strong nuclear interaction. 
B)  the electromagnetic interaction. 
C)  the weak nuclear interaction. 
D)  the gravitational interaction. 
E)  None of these is correct.

Question 19

An antiproton is an atomic particle that has

Accepted Answer

A)  the mass of a proton and the charge of an electron. 
B)  the mass of an electron and the charge of a proton. 
C)  the mass of a neutron and the charge of a proton. 
D)  the mass of a proton and the charge of a neutron. 
E)  the mass of an electron and the charge of a positron. 
A)  the mass of a proton and the charge of an electron. 
B)  the mass of an electron and the charge of a proton. 
C)  the mass of a neutron and the charge of a proton. 
D)  the mass of a proton and the charge of a neutron. 
E)  the mass of an electron and the charge of a positron.

Question 20

We think that the universe is expanding because

Accepted Answer

A)  the light from distant galaxies is very faint. 
B)  the light from distant galaxies is very bright. 
C)  distant galaxies are very small. 
D)  the light from distant galaxies is blueshifted. 
E)  the light from distant galaxies is redshifted. 
A)  the light from distant galaxies is very faint. 
B)  the light from distant galaxies is very bright. 
C)  distant galaxies are very small. 
D)  the light from distant galaxies is blueshifted. 
E)  the light from distant galaxies is redshifted.

Exam 28: Particle Physics

The cosmic background radiation strongly suggests that

The charge of the particle dds is

Which of the following are possible combinations of quarks? 1) 2) 3) 4) 5) 6)

Assuming a radial speed of a galaxy to be 100 km/s from us and Hubble's constant to be 23 km/s/106 c · y, how far is the galaxy from us?

Which of the following choices lists the four known types of forces in nature in order of decreasing strength?

The charge of the d quark is

In the standard model,

Virtual photons are particles that mediate the Coulomb force and travel at the speed of light. What is the approximate energy of the virtual photons that mediate between the ground state electron and the proton in a hydrogen atom? The radius of the electron in the ground state is 0.053 nm.

The cosmic background radiation is an important aspect of the Big Bang theory because it

The conservation law violated by the reaction p → π0 + e+ is the conservation of

A particle and its antiparticle must have

Redshift measurements of a galaxy yield a recession speed of 1700 km/s. Hubble's constant H is 23-km/s/106 ly. The distance to the galaxy is approximately

The charge of the particle is

The reaction e+ + e- →

Forces between electrons or positrons and nucleons that result in beta decay are best understood in terms of

An antiproton is an atomic particle that has

We think that the universe is expanding because

Introduction to Physics

Linear Motion

Motion in Two and Three Dimensions

Forces and Motion I: Newtons Laws

Forces and Motion II: Applications

Work and Energy

Momentum, Collisions, and the Center of Mass

Rotational Motion

Elastic Properties of Matter: Stress and Strain

Gravitation

Fluids

Oscillations

Waves

Thermodynamics I

Thermodynamics II

Electrostatics I: Electric Charge, Forces, and Fields

Electrostatics II: Electric Potential Energy and Electric Potential

Electric Charges in Motion

Magnetism

Electromagnetic Induction

Alternating-Current Circuits

Electromagnetic Waves

Wave Properties of Light

Geometrical Optics

Relativity

Quantum Physics and Atomic Structure

Nuclear Physics

Filters

Assuming a radial speed of a galaxy to be 100 km/s from us and Hubble's constant to be 23 km/s/10⁶ c · y, how far is the galaxy from us?

The conservation law violated by the reaction p → π⁰ + e⁺ is the conservation of

Redshift measurements of a galaxy yield a recession speed of 1700 km/s. Hubble's constant H is 23-km/s/10⁶ ly. The distance to the galaxy is approximately

The reaction e⁺ + e^- →