Deck 12: Special Relativity and Elementary Particles

Question 1

Bosons are force-carrying particles.

Answer 1

False

Question 2

Because of the equivalence of mass and energy, an electron and a positron, which are two massive particles, can annihilate when they come together to produce two photons, which have no mass.

Answer 2

True

Question 3

Because of time dilation, if a twin goes on a trip in a high-speed rocket ship, when she returns home she will be younger than her twin sister who did not go on the trip.

Answer 3

True

Question 4

Any particle with spin obeys the Pauli exclusion principle.

Question 5

A lepton interacts via the strong interaction.

Question 6

Because of their short lifetimes, very few muons that are produced in the upper atmosphere at high speeds should be observed at the surface of the Earth. Yet we detect large numbers of muons at ground level because of the Pauli exclusion principle.

Question 7

A fermion has integral spin.

Question 8

Special relativity predicts that moving clocks run slow.

Question 9

Hadrons are particles that interact via the strong force.

Question 10

Short range interactions generally have carrier particles of greater mass than those for long range interactions.

Question 11

Leptons are built out of quarks.

Question 12

The four fundamental forces in nature are the strong, weak, electromagnetic, and gravitational interactions.

Question 13

Special relativity predicts that the length of a moving object will be elongated in the direction of motion.

Question 14

According to special relativity, at speeds approaching the speed of light, the kinetic energy of a moving object is not equal to 1/2 mv² .

Question 15

Because of the equivalence of energy and mass, a gamma ray, which is a high energy photon, can "disappear," and in its place there will be produced an electron and a positron, which both have mass.

Question 16

The speed of light is a relativistically invariant quantity.

Question 17

Einstein's famous equation E  = mc² is a statement of the equivalence of energy and the square of the speed of light.

Question 18

If a 1-kg mass is completely converted into energy, the amount of energy released would be
9 × 10¹⁶ J.

Question 19

Since the rest energy of an electron and its antiparticle a positron is 0.511 MeV, a gamma ray must have an energy larger than 1.022 MeV to produce an electron-positron pair.

Question 20

A boson has half-integral spin.

Question 21

Baryon number is conserved in all interactions.

Question 22

The quark and antiquark in a meson are always of the same flavor.

Question 23

Charm, beauty, and truth are three quantum numbers for quarks.

Question 24

Leptons are the fundamental particles that are the building blocks of hadrons.

Question 25

Steven Weinberg, Abdus Salam, and Sheldon Glashow shared the 1979 Nobel Prize in physics for their development of GUTs.

Question 26

Quarks are held together by the color force. Electrons are made of quarks.

Question 27

All quarks have 1/3 the electric charge of an electron.

Question 28

The quark structure of the neutron is udd.

Question 29

Some antiparticles are identical to the particles they correspond to.

Question 30

Every particle has a corresponding antiparticle.

Question 31

The strong force depends upon the electric charge of the particles involved.

Question 32

Strangeness is conserved observed in strong and electromagnetic interactions, but not in weak interactions.

Question 33

According to the standard model of elementary particle physics, there are six flavors of quarks, each of which comes in three colors.

Question 34

The color force between quarks is carried by mesons.

Question 35

Recent experiments suggest that the lifetime of the proton is over 10 ³³ years, more than what is predicted by the simplest grand unified theories.

Question 36

The quark structure of the proton is uud.

Question 37

There are three flavors of quarks.

Question 38

The color force is carried by gluons but gluons do not have color charge themselves.

Question 39

Electroweak theory results in models for combining the electromagnetic, weak and strong nuclear interactions into a single basic force.

Question 40

A photon is a boson.

Question 41

What is meant by neutrino oscillations?

A) oscillating movement of neutrinos
B) one neutrino type (e.g., muon neutrinos) changing into another (e.g., tau neutrinos)
C) random changes in mass of neutrinos
D) none of the above

Question 42

The notation used to represent an antiparticle is

A) the particle symbol with a bar over it.
B) e ⁺ , in the case of the positron.
C) μ ⁺ , in the case of the antimuon.
D) all of the above.

Question 43

Einstein's famous equation E  = mc² is a statement of

A) time dilation.
B) length contraction.
C) the equivalence of mass and energy.
D) the principle of relativity.
E) none of the above.

Question 44

What is different between a particle and its antiparticle?

A) opposite electric charge
B) opposite strangeness
C) opposite charm
D) all of the above

Question 45

What is the symbol for a photon?

A) n
B)
C)
D) none of the above

Question 46

The prediction of special relativity that moving clocks run slow is

A) time dilation.
B) length contraction.
C) the equivalence of mass and energy.
D) the principle of relativity.
E) none of the above.

Question 47

When it comes near a heavy nucleus, a gamma ray, which is a high energy photon, can "disappear," and in its place there will be produced an electron and a positron, which both have mass. This pair production is an example of

A) time dilation.
B) length contraction.
C) the equivalence of mass and energy.
D) the principle of relativity.
E) none of the above.

Question 48

Two observers, A and B, move relative to each other. A claims B's clocks run slow. In this case, B will claim A's clocks

A) run fast.
B) run slow, too.
C) are no good.
D) none of the above

Question 49

In a particle reaction, the number of baryons going into the reaction must equal the number emerging from the reaction.

Question 50

An electron and a positron, which are two massive particles, can annihilate when they come together to produce two photons, which have no mass. This pair annihilation is an example of

A) time dilation.
B) length contraction.
C) the equivalence of mass and energy.
D) the principle of relativity.
E) none of the above.

Question 51

All neutrinos are left handed.

Question 52

The spin of elementary particles is quantized.

Question 53

When a particle and antiparticle meet, they are said to annihilate each other. What does this mean?

A) They explode into tiny fragments.
B) They are destroyed, and turned into an equivalent amount of energy.
C) They merge and simply disappear.
D) none of the above

Question 54

If you are driving down a highway at 65 mph with your headlights on, the speed of the light emitted from your headlights as seen by a person standing on the side of the road is

A) c.
B) c + 65 mph.
C) slightly greater than c.
D) none of the above.

Question 55

What is the mass of an electron in MeV/c ²?

A) 0.511 MeV/c ²
B) 105.7 MeV/c ²
C) 1777 MeV/c ²
D) none of the above

Question 56

Mesons are composed of three-quark combinations.

Question 57

The rest energy of an electron and its antiparticle, a positron, is 0.511 MeV. In order to produce an electron-positron pair, a gamma ray must have an energy larger than 1.022 MeV because of

A) time dilation.
B) length contraction.
C) the equivalence of mass and energy.
D) the principle of relativity.
E) none of the above.

Question 58

An elementary particle has a measurable size.

Question 59

What is the symbol for a neutrino?

A) n
B)
C)
D) none of the above

Question 60

The prediction from special relativity that the length of a moving object will be shortened in the direction of motion is

A) time dilation.
B) length contraction.
C) the equivalence of mass and energy.
D) the principle of relativity.
E) none of the above.

Question 61

How many quark colors are there?

A) 1
B) 3
C) 6
D) none of the above

Question 62

If you do an experiment on Earth, and then do an identical experiment in a jet plane moving uniformly at a high speed, you get identical results from both experiments. This is an example of

A) time dilation.
B) length contraction.
C) the equivalence of mass and energy.
D) the principle of relativity.
E) none of the above.

Question 63

From the point of view of an observer on the Earth, a muon produced high in the atmosphere can reach the ground before decaying because

A) relativity gives it extra time to get there.
B) of the uncertainty principle.
C) it is a short distance to the ground.
D) relativity shortens the distance to the ground.

Question 64

What is the quark structure of a proton?

A) uud
B) udd
C) uuu
D) ddd
E) the question does not make sense

Question 65

Electrons are "spin one-half," photons are

A) also spin one-half.
B) spin zero.
C) spin one.
D) none of the above.

Question 66

What is the quark structure of a neutron?

A) uud
B) udd
C) uuu
D) ddd
E) the question does not make sense

Question 67

A particle with an integral spin is a

A) boson.
B) lepton.
C) fermion.
D) hadron.
E) muon.

Question 68

How many quark flavors are there?

A) 1
B) 3
C) 6
D) none of the above

Question 69

From the point of view of a muon produced high in the atmosphere, the reason it can get to the ground before it decays is because

A) relativity gives it extra time to get there.
B) of the uncertainty principle.
C) it is a short distance to the ground.
D) relativity shortens the distance to the ground.

Question 70

"Half-integral spin" means spin

A) 1/2.
B) 1/2, 1, 3/2, 2, ...
C) 1/2, 3/2, 5/2, ...
D) none of the above

Question 71

What's the quark structure of an antiproton?

A) ddu
B) bbt
C)
D) none of the above

Question 72

If a 1-kg mass is completely converted into energy, the amount of energy released would be

A) 0.333 J.
B) 1 J.
C) 3 × 10⁸ J.
D) 9 × 10¹⁶ J.
E) none of the above.

Question 73

A fundamental force in nature is the

A) strong interaction.
B) weak interaction.
C) electromagnetic interaction.
D) gravitational interaction.
E) all of the above

Question 74

At speeds approaching the speed of light, the kinetic energy of a moving object is equal to

A) 1/2 mv ².
B) 1/2 mc ².
C) .
D) .
E) none of the above.

Question 75

A particle with a half-integral spin is a

A) boson.
B) lepton.
C) fermion.
D) hadron.
E) muon.

Question 76

What is the quark structure of an electron?

A) uud
B) udd
C) uuu
D) ddd
E) the question does not make sense

Question 77

The color force between quarks is carried by

A) mesons.
B) the strong force.
C) leptons.
D) gluons.
E) none of the above.

Question 78

A particle with ____________ obeys the Pauli exclusion principle.

A) zero rest mass
B) very high energy
C) half-integral spin
D) integral spin
E) charm

Question 79

Because of their short lifetimes, very few muons that are produced in the upper atmosphere at high speeds should be observed at the surface of the Earth. Yet we detect large numbers of muons at ground level because of

A) time dilation.
B) length contraction.
C) the equivalence of mass and energy.
D) the principle of relativity.
E) none of the above.

Question 80

If a twin goes on a trip in a high-speed rocket ship, when she returns home she will be younger than her twin sister who did not go on the trip because of

A) time dilation.
B) length contraction.
C) the equivalence of mass and energy.
D) the principle of relativity.
E) none of the above.