Question 1

The reaction e+ + e-  →\rightarrow→γ\gammaγ  +  γ\gammaγ

Accepted Answer

A)   describes the annihilation of a positron.
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)   is an electron-positron reaction.
E)   All of these are correct.

Question 2

The fact that the reaction 37Cl +37Cl +    \rightarrow 37Ar + e- is not observed whereas the reaction P +   \rightarrow  n + e+ is observed is understandable in terms of the conservation of A)  baryon number B)  energy C)  lepton number D)  charge E)  angular momentum " class="answers-bank-image d-inline" rel="preload" >   →\rightarrow→ 37Ar + e- is not observed whereas the reaction
P +  →\rightarrow→  n + e+ is observed is understandable in terms of the conservation of

Accepted Answer

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

Question 3

A thousand years after the "Big Bang" the background temperature of the universe was at   ∽\backsim∽  105 K. The peak wavelength of the blackbody radiation at that temperature is

Accepted Answer

A)   29 nm
B)   290 nm
C)   56 nm
D)   560 nm
E)   730 nm

Question 4

According to Hubble's law, the age of the universe is

Accepted Answer

A)   approximately 6000 years.
B)   less than 6000 years.
C)   roughly 1 billion years.
D)   too great to estimate.
E)   between 10 and 15 billion years.

Question 5

In quantum electrodynamics (QED) , the electromagnetic field is described in terms of

Accepted Answer

A)   the interaction of electrons.
B)   hadrons.
C)   action at a distance.
D)   the weak nuclear interaction.
E)   the interaction of photons.

Question 6

The numbers L = 0 and B = 0 describe

Accepted Answer

A)   a particle other than a lepton or a baryon.
B)   a lepton and an antibaryon.
C)   an antilepton and a baryon.
D)   an antilepton and an antibaryon.
E)   a lepton and a baryon.

Question 7

In the standard model, weak charge is

Accepted Answer

A)   the charge associated with the gravitational force.
B)   carried by leptons and quarks.
C)   carried by quarks and gluons but not leptons.
D)   carried by photons.
E)   a property of the W± and the Z particles.

Question 8

Particles that have zero spin or integral spin

Accepted Answer

A)   are called bosons.
B)   are called fermions.
C)   must be in different quantum states.
D)   include protons, neutrons, and neutrinos.
E)   None of these is correct.

Question 9

In the Standard Model, as with the leptons, there are 3 generations of quarks (u&d, c&s, and t&b) . The reason for this is

Accepted Answer

A)   because a baryon contains 3 quarks.
B)   because the electric charge of the quarks is +1/3 or -2/3 of e.
C)   because each quark has a baryon number of 1/3.
D)   all of the above.
E)   something we do not yet understand.

Question 10

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

Accepted Answer

A)   36 * 106 c·y
B)   47 * 106 c·y
C)   53 *106 c·y
D)   66 * 106 c·y
E)   74 * 106 c·y

Question 11

Conservation laws that describe events involving the elementary particles include the conservation of

Accepted Answer

A)   energy.
B)   linear and angular momentum.
C)   electric charge.
D)   baryon and lepton numbers.
E)   All of these are correct.

Question 12

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.

Question 13

There is evidence that the universe is expanding like a loaf of raisin bread baking in an oven. This means that

Accepted Answer

A)   some clusters of galaxies are not getting farther away from other clusters of galaxies.
B)   the expansion looks different from each cluster of galaxies.
C)   the expansion looks the same from each cluster of galaxies.
D)   we should be able to determine the location of the center of the expansion.
E)   the universe will eventually collapse.

Question 14

Leptons

Accepted Answer

A)   are less massive than the lightest hadron.
B)   include electrons, muons, and neutrinos.
C)   participate in the weak interaction.
D)   have significantly different masses.
E)   All of these are correct.

Question 15

Hadrons are thought to be

Accepted Answer

A)   without structure.
B)   composed of quarks.
C)   composed of electrons.
D)   responsible for the gravitational interaction.
E)   extremely stable particles.

Question 16

Spin  particles

Accepted Answer

A)   have spins that are integral multiples of 
B)   are called fermions.
C)   obey the Pauli exclusion principle.
D)   include protons, neutrons, and neutrinos.
E)   All of these are correct.

Question 17

Particles that participate in the weak interaction but not the strong interaction are called

Accepted Answer

A)   neutrinos
B)   hadrons
C)   leptons
D)   electrons
E)   photons

Question 18

Current thought is that all matter is composed of

Accepted Answer

A)   six quarks.
B)   four quarks and four leptons.
C)   six leptons.
D)   six quarks and four leptons.
E)   six quarks and six leptons.

Question 19

Which of the following are possible combinations of quarks?

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

Question 20

The charge of the particle  is

Accepted Answer

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

Exam 21: Elementary Particles and the Beginning of the Universe

Correct Answer
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Spin particles

Correct Answer
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Redshift measurements of a galaxy yield a recession of 1700 km/s. Hubble's constant H is 23 km/s/10⁶ c·y. The distance to the galaxy is approximately

Correct Answer
verified

Hadrons are thought to be

Correct Answer
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A thousand years after the "Big Bang" the background temperature of the universe was at $\backsim$ 10⁵ K. The peak wavelength of the blackbody radiation at that temperature is

Correct Answer
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The charge of the particle is

Correct Answer
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According to Hubble's law, the age of the universe is

Correct Answer
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In the standard model, weak charge is

Correct Answer
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The numbers L = 0 and B = 0 describe

Correct Answer
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Which of the following are possible combinations of quarks?

Correct Answer
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Leptons

Correct Answer
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Conservation laws that describe events involving the elementary particles include the conservation of

Correct Answer
verified

Current thought is that all matter is composed of

Correct Answer
verified

The reaction e⁺ + e^- $\rightarrow$ $\gamma$ + $\gamma$

Correct Answer
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In quantum electrodynamics (QED) , the electromagnetic field is described in terms of

Correct Answer
verified

Particles that have zero spin or integral spin

Correct Answer
verified

In the Standard Model, as with the leptons, there are 3 generations of quarks (u&d, c&s, and t&b) . The reason for this is

Correct Answer
verified

The cosmic background radiation strongly suggests that

Correct Answer
verified

There is evidence that the universe is expanding like a loaf of raisin bread baking in an oven. This means that

Correct Answer
verified

Particles that participate in the weak interaction but not the strong interaction are called

Correct Answer
verified

Exam 21: Elementary Particles and the Beginning of the Universe

The fact that the reaction 37Cl + →\rightarrow→ 37Ar + e- is not observed whereas the reaction P +11efbfba_b1a8_16af_a19f_e32c5f3598e7_TB6081_00 →\rightarrow→ n + e+ is observed is understandable in terms of the conservation of

Correct AnswerverifiedShow Answer

Spin particles

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Hadrons are thought to be

Correct AnswerverifiedShow Answer

A thousand years after the "Big Bang" the background temperature of the universe was at ∽\backsim∽ 105 K. The peak wavelength of the blackbody radiation at that temperature is

Correct AnswerverifiedShow Answer

The charge of the particle is

Correct AnswerverifiedShow Answer

According to Hubble's law, the age of the universe is

Correct AnswerverifiedShow Answer

In the standard model, weak charge is

Correct AnswerverifiedShow Answer

The numbers L = 0 and B = 0 describe

Correct AnswerverifiedShow Answer

Which of the following are possible combinations of quarks?

Correct AnswerverifiedShow Answer

Leptons

Correct AnswerverifiedShow Answer

Conservation laws that describe events involving the elementary particles include the conservation of

Correct AnswerverifiedShow Answer

Current thought is that all matter is composed of

Correct AnswerverifiedShow Answer

The reaction e+ + e- →\rightarrow→γ\gammaγ + γ\gammaγ

Correct AnswerverifiedShow Answer

In quantum electrodynamics (QED) , the electromagnetic field is described in terms of

Correct AnswerverifiedShow Answer

Particles that have zero spin or integral spin

Correct AnswerverifiedShow Answer

In the Standard Model, as with the leptons, there are 3 generations of quarks (u&d, c&s, and t&b) . The reason for this is

Correct AnswerverifiedShow Answer

The cosmic background radiation strongly suggests that

Correct AnswerverifiedShow Answer

There is evidence that the universe is expanding like a loaf of raisin bread baking in an oven. This means that

Correct AnswerverifiedShow Answer

Particles that participate in the weak interaction but not the strong interaction are called

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

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

Correct Answer
verified

Correct Answer
verified

A thousand years after the "Big Bang" the background temperature of the universe was at $\backsim$ 10⁵ K. The peak wavelength of the blackbody radiation at that temperature is

Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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The reaction e⁺ + e^- $\rightarrow$ $\gamma$ + $\gamma$

Correct Answer
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Correct Answer
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