Deck 44: Quarks, Leptons, and the Big Bang

Question 1

Two baryons interact to produce pions only, the original baryons disappearing.One of the baryons must have been:

A)a proton
B)an omega minus
C)a sigma
D)an antiparticle
E)none of these

Answer 1

an antiparticle

Question 2

When a kaon decays via the strong interaction the products must include a:

A)baryon
B)lepton
C)strange particle
D)electron
E)neutrino

Answer 2

strange particle

Question 3

Different types of neutrinos can be distinguished from each other by:

A)the directions of their spins
B)the leptons with which they interact
C)the baryons with which they interact
D)the number of photons that accompany them
E)their baryon numbers

Answer 3

the leptons with which they interact

Question 4

Which of the following statements is correct?

A)All leptons are bosons.
B)All hadrons are fermions.
C)The two types of mesons are leptons and baryons.
D)The two types of hadrons are mesons and baryons.
E)The two types of leptons are mesons and fermions.

Question 5

Which of the following particles is stable?

A)Neutron
B)Proton
C)Pion
D)Muon
E)Kaon

Question 6

A particle with spin angular momentum is called a:

A)lepton
B)hadron
C)fermion
D)boson
E)electron

Question 7

All leptons interact with each other via the:

A)strong force
B)weak force
C)electromagnetic force
D)strange force
E)none of these

Question 8

An electron participates in:

A)the electromagnetic and weak forces only
B)the strong and weak forces only
C)the electromagnetic and gravitational forces only
D)the electromagnetic, gravitational, and weak forces only
E)the electromagnetic, gravitational, and strong forces only

Question 9

A particle with spin angular momentum is called a:

A)lepton
B)hadron
C)fermion
D)boson
E)electron

Question 10

A particle can decay to particles with greater rest mass:

A)only if antiparticles are produced
B)only if photons are also produced
C)only if neutrinos are also produced
D)only if the original particle has kinetic energy
E)never

Question 11

A proton cannot decay into a neutron, a positron, and an electron neutrino.Which of the following conservation laws would be violated if it did?

A)Charge
B)Linear momentum
C)Angular momentum
D)Energy
E)None of the above

Question 12

An example of a boson is a:

A)photon
B)electron
C)neutrino
D)proton
E)neutron

Question 13

The interaction $\pi$ ^- + p $\rightarrow$ K^- + $\Sigma$ ⁺ violates the principle of conservation of:

A)baryon number
B)lepton number
C)strangeness
D)angular momentum
E)none of these

Question 14

Two particles interact to produce only photons, with the original particles disappearing.The particles must have been:

A)mesons
B)strange particles
C)strongly interacting
D)leptons
E)a particle-antiparticle pair

Question 15

Strangeness is conserved in:

A)all particle decays
B)no particle decays
C)all weak particle decays
D)all strong particle decays
E)some strong particle decays

Question 16

All particles with spin angular momentum :

A)interact via the strong force
B)travel at the speed of light
C)obey the Pauli exclusion principle
D)have non-zero rest mass
E)are charged

Question 17

A neutron cannot decay into a neutrino and an antineutrino.This decay would violate baryon number conservation and which other conservation law?

A)Energy
B)Lepton number
C)Electric charge
D)Linear momentum
E)Angular momentum

Question 18

An example of a fermion is a:

A)photon
B)pion
C)neutrino
D)kaon
E)none of these

Question 19

A neutral lepton cannot decay into two neutrinos.Of the following conservation laws, which would be violated if it did?

A)Energy
B)Baryon number
C)Linear Momentum
D)Angular momentum
E)None of the above

Question 20

The stability of the proton is predicted by the laws of conservation of energy and conservation of:

A)momentum
B)angular momentum
C)baryon number
D)lepton number
E)strangeness

Question 21

Compared to the lifetimes of particles that decay via the weak interaction, the lifetimes of particles that decay via the strong interaction are:

A)10^-23 times as long
B)10^-12 times as long
C)10¹² times as long
D)10²⁴ times as long
E)about the same

Question 22

The interaction $\pi$ ^- + p $\rightarrow$ $\pi$ ^- + $\Sigma$ ⁺ violates the principle of conservation of:

A)baryon number
B)lepton number
C)strangeness
D)angular momentum
E)none of these

Question 23

In order of increasing strength the four basic interactions are:

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

Question 24

Any meson is a combination of:

A)three quarks
B)two quarks and an antiquark
C)one quark and two antiquarks
D)one quark and one antiquark
E)two quarks

Question 25

Quarks are the constituents of:

A)all particles
B)all leptons
C)all strongly interacting particles
D)only strange particles
E)only mesons

Question 26

A certain process produces baryons that decay with a lifetime of 4 * 10^-24 s.The decay is a result of:

A)the gravitational interaction
B)the weak interaction
C)the electromagnetic interaction
D)the strong interaction
E)some combination of the above

Question 27

The quark content of a proton is:

A)uuu
B)uud
C)udd
D)ddd
E)uds

Question 28

A baryon is a combination of:

A)three quarks
B)two quarks and an antiquark
C)one quark and two antiquarks
D)one quark and one antiquark
E)two quarks

Question 29

How many different flavors of quarks are there (not counting antiquarks)?

A)1
B)3
C)6
D)12
E)18

Question 30

The up quark u has charge +2/3 and strangeness 0; the down quark d has charge -1/3 and strangeness 0; the strange quark s has charge -1/3 and strangeness -1.This means there can be no meson with:

A)charge 0 and strangeness -1
B)charge -1 and strangeness -1
C)charge +1 and strangeness -1
D)charge -1 and strangeness +1
E)charge 0 and strangeness +1

Question 31

All known quarks and antiquarks have:

A)charges that are multiples of e and integer baryon numbers
B)charges that are multiples of e and baryon numbers that are either +1/3 or -1/3
C)charges that are multiples of e/3 and integer baryon numbers
D)charges that are multiples of e/3 and baryon numbers that are either +1/3 or -1/3
E)charges that are multiples of 2e/3 and baryon numbers that are either +1/3 or -1/3

Question 32

A baryon with strangeness 0 decays via the strong interaction into two particles, one of which is a baryon with strangeness +1.The other is:

A)a baryon with strangeness 0
B)a baryon with strangeness +1
C)a baryon with strangeness -1
D)a meson with strangeness +1
E)a meson with strangeness -1

Question 33

A baryon with strangeness -1 decays via the strong interaction into two particles, one of which is a baryon with strangeness 0.The other is:

A)a baryon with strangeness 0
B)a baryon with strangeness +1
C)a meson with strangeness -1
D)a meson with strangeness +1
E)a meson with strangeness 0

Question 34

A down quark can be changed into an up quark (plus other particles perhaps)by:

A)the gravitational interaction
B)the weak interaction
C)the electromagnetic interaction
D)the strong interaction
E)none of these

Question 35

The two basic interactions that have finite ranges are:

A)electromagnetic and gravitational
B)electromagnetic and strong
C)electromagnetic and weak
D)gravitational and weak
E)weak and strong

Question 36

The color theory explains why quarks:

A)form particles in pairs and triplets
B)have charge that is a multiple of e/3
C)have spin
D)have mass
E)none of the above

Question 37

The baryon number of a quark is:

A)0
B)-1/3
C)1/3
D)2/3
E)1

Question 38

Color is carried by:

A)only quarks
B)only leptons
C)only quarks and leptons
D)only quarks and gluons
E)only photons and gluons

Question 39

A certain process produces mesons that decay with a lifetime of 6 * 10^-10 s.The decay is a result of:

A)the gravitational interaction
B)the weak interaction
C)the electromagnetic interaction
D)the strong interaction
E)some combination of the above

Question 40

The up quark u has charge +2e/3 and strangeness 0; the down quark d has charge -e/3 and strangeness 0; the strange quark s has charge -e/3 and strangeness -1.This means there can be no baryon with:

A)charge 0 and strangeness 0
B)charge -e and strangeness -1
C)charge +e and strangeness -1
D)charge +e and strangeness -2
E)charge 0 and strangeness -2

Question 41

The intensity of the microwave background radiation, a remnant of the big bang:

A)is greatest in directions toward the center of the galaxy
B)is least in directions toward the center of the galaxy
C)is proportional to the reciprocal of the distance from us
D)is proportional to the square of the distance from us
E)is nearly the same in all directions

Question 42

Hubble's law is evidence that:

A)the speed of light is increasing
B)the universe is expanding
C)the Earth is slowing down in its orbit
D)galaxies have rotational motion
E)none of the above

Question 43

Dark matter is suspected to exist in the universe because:

A)the night sky is dark between stars
B)the orbital period of stars in the outer parts of a galaxy is greater than the orbital period of stars near the galactic center
C)the orbital period of stars in the outer parts of a galaxy is less than the orbital period of stars near the galactic center
D)the orbital period of stars in the outer parts of a galaxy is about the same as the orbital period of stars near the galactic center
E)all galaxies have about the same mass

Question 44

What discovery in 1998 changed our understanding of the overall history of the universe?

A)The universe is permeated with radiation at microwave frequencies.
B)The universe is expanding, and has been since the Big Bang.
C)The expansion of the universe is slowing, and will eventually reverse, ending in a Big Crunch.
D)The expansion of the universe is accelerating, due to an unknown cause known as dark energy.
E)Rotational measurements of our galaxy and others demonstrated the existence of dark matter.

Question 45

If dark matter did not exist it is likely that:

A)the universe would expand forever
B)the universe would begin contracting soon
C)the night sky would be brighter
D)the night sky would be darker
E)we would be able to see the center of the universe

Question 46

In terms of quark content a beta decay can be written:

A)udd $\rightarrow$ uud + e^- +
B)udd $\rightarrow$ udd + dd + $\nu$
C)udd $\rightarrow$ udd + dd + e^-
D)udd $\rightarrow$ uud + ud + $\nu$
E)udd $\rightarrow$ uud + e⁺ +

Question 47

Objects in the universe are receding from us with a speed that is proportional to:

A)the reciprocal of the square of their distance from us
B)the reciprocal of their distance from us
C)their distance from us
D)the square of their distance from us
E)their distance from the center of the universe

Question 48

A galaxy 200 Mpc from us has a recessional velocity of about 14,000 km/s.If it emits radiation at a wavelength of 121 nm, how much is that wavelength shifted when we observe it?

A)5.7 x 10^-12 m
B)5.7 x 10^-10 m
C)5.7 x 10^-9 m
D)5.7 x 10^-7 m
E)5.7 x 10^-6 m

Question 49

Messenger particles of the electromagnetic interaction are called:

A)gluons
B)photons
C)W and Z
D)gravitons
E)pions

Question 50

Messenger particles of the strong interaction are called:

A)gluons
B)photons
C)W and Z
D)gravitons
E)Higgs

Question 51

The mass of the W boson is 80 GeV/c².During beta decay, a virtual W is created.In order not to visibly violate conservation of energy, what is the longest time the W particle can be in existence?

A)0 s
B)8 x 10^-45 s
C)8 x 10^-36 s
D)8 x 10^-27 s
E)There is no limit on the time the W can exist.

Question 52

The microwave background radiation is a result of the big bang.The big bang also resulted in a uniform distribution of background:

A)electrons
B)quarks
C)gluons
D)neutrinos
E)atoms

Question 53

Baryonic matter (protons and neutrons)comprises what fraction of the total energy of the universe?

A)about 1%
B)about 4%
C)about 23%
D)about 73%
E)almost 100%

Question 54

Messenger particles of the weak interaction are called:

A)gluons
B)photons
C)W and Z
D)gravitons
E)pions

Question 55

The velocities of distant objects in the universe indicate that the time elapsed since the big bang is about:

A)10⁵ y
B)10¹⁰ y
C)10¹⁵ y
D)10²⁰ y
E)10²⁵ y