Deck 12: Special Relativity and Elementary Particles

Question 1

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 1

True

Question 2

A fermion has integral spin.

Answer 2

False

Question 3

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.

Answer 3

True

Question 4

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

Question 5

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 6

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

Question 7

Leptons are built out of quarks.

Question 8

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 9

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

Question 10

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

Question 11

Hadrons are particles that interact via the strong force.

Question 12

A boson has half-integral spin.

Question 13

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.

Question 14

Special relativity predicts that moving clocks run slow.

Question 15

Bosons are force-carrying particles.

Question 16

Any particle with spin obeys the Pauli exclusion principle.

Question 17

The speed of light is a relativistically invariant quantity.

Question 18

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 19

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

Question 20

A lepton interacts via the strong interaction.

Question 21

There are three flavors of quarks.

Question 22

Baryon number is conserved in all interactions.

Question 23

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

Question 24

Recent experiments suggest that the lifetime of the proton is over 10³³ years,more than what is predicted by the simplest grand unified theories.

Question 25

A photon is a boson.

Question 26

The quark structure of the proton is uud.

Question 27

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

Question 28

The quark structure of the neutron is udd.

Question 29

Every particle has a corresponding antiparticle.

Question 30

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

Question 31

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

Question 32

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

Question 33

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

Question 34

Some antiparticles are identical to the particles they correspond to.

Question 35

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

Question 36

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

Question 37

The color force between quarks is carried by mesons.

Question 38

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

Question 39

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

Question 40

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

Question 41

What is the symbol for a photon?

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

Question 42

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 43

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 44

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 45

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

Question 46

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 47

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 48

The spin of elementary particles is quantized.

Question 49

What is the symbol for a neutrino?

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

Question 50

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 51

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 52

What is the mass of an electron in MeV/c²?

A)0.511 MeV/c²
B)105.7 MeV/c²
C)1777 MeV/c²
D)none of the above

Question 53

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 54

Mesons are composed of three-quark combinations.

Question 55

All neutrinos are left handed.

Question 56

An elementary particle has a measurable size.

Question 57

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 58

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 59

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 60

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 61

Gluons

A)are carriers of the color force.
B)possess color charge.
C)can interact with each other via the color force.
D)can form glueballs.
E)all of the above

Question 62

How many quark colors are there?

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

Question 63

The color force between quarks is carried by

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

Question 64

What is the quark structure of an electron?

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

Question 65

What's the quark structure of an antiproton?

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

Question 66

A particle with a half-integral spin is a

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

Question 67

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 68

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 69

"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 70

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 71

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 72

A particle with an integral spin is a

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

Question 73

Electrons are "spin one-half," photons are

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

Question 74

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 75

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

A)1/2 mv².
B)1/2 mc².
C)
)
D)
)
E)none of the above.

Question 76

How many quark flavors are there?

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

Question 77

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.

Question 78

What is the quark structure of a neutron?

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

Question 79

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 80

What is the quark structure of a proton?

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