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Physic
Q:
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
Q:
The velocities of distant objects in the universe indicate that the time elapsed since the big bang is about:
A) 105y
B) 1010y
C) 1015y
D) 1020y
E) 1025y
Q:
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 10-12m
B) 5.7 x 10-10m
C) 5.7 x 10-9m
D) 5.7 x 10-7m
E) 5.7 x 10-6m
Q:
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
Q:
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
Q:
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
Q:
Messenger particles of the weak interaction are called:
A) gluons
B) photons
C) W and Z
D) gravitons
E) pions
Q:
Messenger particles of the strong interaction are called:
A) gluons
B) photons
C) W and Z
D) gravitons
E) Higgs
Q:
Messenger particles of the electromagnetic interaction are called:
A) gluons
B) photons
C) W and Z
D) gravitons
E) pions
Q:
The mass of the W boson is 80GeV/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 10-45s
C) 8 x 10-36s
D) 8 x 10-27s
E) There is no limit on the time the W can exist.
Q:
In terms of quark content a beta decay can be written:
Q:
The quark content of a meson is:
Q:
The quark content of a proton is:
A) uuu
B) uud
C) udd
D) ddd
E) uds
Q:
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 -1B) charge -1 and strangeness -1C) charge +1 and strangeness -1D) charge -1 and strangeness +1E) charge 0 and strangeness +1
Q:
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 0B) charge -eand strangeness -1C) charge +eand strangeness -1D) charge +eand strangeness -2E) charge 0 and strangeness -2
Q:
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
Q:
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
Q:
Quarks are the constituents of:
A) all particles
B) all leptons
C) all strongly interacting particles
D) only strange particles
E) only mesons
Q:
How many different flavors of quarks are there (not counting antiquarks)?
A) 1
B) 3
C) 6
D) 12
E) 18
Q:
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
Q:
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
Q:
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
Q:
Compared to the lifetimes of particles that decay via the weak interaction, the lifetimes of particles that decay via the strong interaction are:A) 10-23times as longB) 10-12times as longC) 1012times as longD) 1024times as longE) about the same
Q:
A certain process produces mesons that decay with a lifetime of 6 x10-10s. The decay is a result of:A) the gravitational interactionB) the weak interactionC) the electromagnetic interactionD) the strong interactionE) some combination of the above
Q:
A certain process produces baryons that decay with a lifetime of 4 x10-24s. The decay is a result of:A) the gravitational interactionB) the weak interactionC) the electromagnetic interactionD) the strong interactionE) some combination of the above
Q:
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
Q:
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
Q:
The baryon number of a quark is:A) 0B) -1/3C) 1/3D) 2/3E) 1
Q:
All known quarks and antiquarks have:A) charges that are multiples of eand integer baryon numbersB) charges that are multiples of eand baryon numbers that are either +1/3 or -1/3C) charges that are multiples of e/3 and integer baryon numbersD) charges that are multiples of e/3 and baryon numbers that are either +1/3 or -1/3E) charges that are multiples of 2e/3 and baryon numbers that are either +1/3 or -1/3
Q:
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 0B) a baryon with strangeness +1C) a baryon with strangeness -1D) a meson with strangeness +1E) a meson with strangeness -1
Q:
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 0B) a baryon with strangeness +1C) a meson with strangeness -1D) a meson with strangeness +1E) a meson with strangeness 0
Q:
The interaction violates the principle of conservation of:A) baryon numberB) lepton numberC) strangenessD) angular momentumE) none of these
Q:
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
Q:
When a kaon decays via the strong interaction the products must include a:
A) baryon
B) lepton
C) strange particle
D) electron
E) neutrino
Q:
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
Q:
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
Q:
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
Q:
represents a pion (a meson), represents a muon (a lepton), verepresents an electron neutrino (a lepton), and represents a muon neutrino (a lepton). Which of the following decays might occur?
Q:
Which of the following particles has a lepton number of +1?
Q:
Which of the following particles has a lepton number of zero?
Q:
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
Q:
The interaction violates the principle of conservation of:A) baryon numberB) lepton numberC) strangenessD) angular momentumE) none of these
Q:
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
Q:
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
Q:
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
Q:
All leptons interact with each other via the:
A) strong force
B) weak force
C) electromagnetic force
D) strange force
E) none of these
Q:
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
Q:
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.
Q:
All particles with spin angular momentum :A) interact via the strong forceB) travel at the speed of lightC) obey the Pauli exclusion principleD) have non-zero rest massE) are charged
Q:
An example of a boson is a:
A) photon
B) electron
C) neutrino
D) proton
E) neutron
Q:
An example of a fermion is a:
A) photon
B) pion
C) neutrino
D) kaon
E) none of these
Q:
A particle with spin angular momentum is called a:A) leptonB) hadronC) fermionD) bosonE) electron
Q:
A particle with spin angular momentum is called a:A) leptonB) hadronC) fermionD) bosonE) electron
Q:
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
Q:
Which of the following particles is stable?
A) Neutron
B) Proton
C) Pion
D) Muon
E) Kaon
Q:
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%
Q:
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.
Q:
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
Q:
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
Q:
In laser fusion, the laser light is:
A) emitted by the reacting nuclei
B) used to cause transitions between nuclear energy levels
C) used to cause transitions between atomic energy levels
D) used to replace the emitted gamma rays
E) used to heat the fuel pellet
Q:
Most laser fusion projects attempt:
A) proton-proton fusion
B) proton-deuteron fusion
C) deuteron-deuteron fusion
D) deuteron-triton fusion
E) triton-triton fusion
Q:
Compared to fusion in a tokamak, laser fusion makes use of:
A) smaller particle number densities
B) greater particle number densities
C) longer confinement times
D) higher temperatures
E) lower temperatures
Q:
Most magnetic confinement projects attempt:
A) proton-proton fusion
B) proton-deuteron fusion
C) deuteron-deuteron fusion
D) deuteron-triton fusion
E) triton-triton fusion
Q:
Tokamaks confine deuteron plasmas using:
A) thick steel walls
B) magnetic fields
C) laser beams
D) vacuum tubes
E) electric fields
Q:
Lawson's number is . If the density of deuteron nuclei is what should the confinement time be to achieve sustained fusion?A) 16 msB) 50 msC) 160 msD) 250 msE) 20 s
Q:
For purposes of a practical (energy producing) reaction one wants a disintegration energy Qthat is:
A) positive for fusion reactions and negative for fission reactions
B) negative for fusion reactions and positive for fission reactions
C) negative for both fusion and fission reactions
D) positive for both fusion and fission reactions
E) as close to zero as possible for both fusion and fission reactions
Q:
For a controlled nuclear fusion reaction, one needs:
A) high number density nand high temperature T
B) high number density nand low temperatureT
C) low number density nand high temperature T
D) low number density nand low temperature T
E) high number density nand temperature T = 0 K
Q:
Which of the following chemical elements is not produced by thermonuclear fusion in stars?A) Carbon (Z= 6, A=12)B) Silicon (Z= 14, A=28)C) Oxygen (Z= 8, A=16)D) Mercury (Z= 80, A=200)E) Chromium (Z= 24, A=52)
Q:
Nuclear fusion in stars produces all the chemical elements with mass numbers less than:
A) 56
B) 66
C) 70
D) 82
E) 92
Q:
The Sun has enough hydrogen in its core to continue fusing hydrogen to helium for about another:
A) million years
B) five million years
C) five billion years
D) five trillion years
E) The Sun can continue to fuse hydrogen to helium indefinitely.
Q:
The energy released in a complete proton-proton cycle is about:
A) 3 keV
B) 30 keV
C) 3 MeV
D) 30 MeV
E) 300 MeV
Q:
The overall proton-proton cycle is equivalent to:
Q:
The first step of the proton-proton cycle is:
Q:
Nuclear fusion in the Sun is increasing its supply of:
A) hydrogen
B) helium
C) nucleons
D) positrons
E) neutrons
Q:
Most of the energy produced by the Sun is due to:
A) nuclear fission
B) nuclear fusion
C) chemical reaction
D) gravitational collapse
E) induced emfs associated with the Sun's magnetic field
Q:
High temperatures are required in thermonuclear fusion so that:
A) some nuclei are moving fast enough to overcome the barrier to fusion
B) there is a high probability some nuclei will strike each other head on
C) the atoms are ionized
D) thermal expansion gives the nuclei more room
E) the uncertainty principle can be circumvented
Q:
The barrier to fusion comes about because protons:
A) attract each other via the strong nuclear force
B) repel each other electrically
C) produce magnetic fields
D) attract neutrons via the strong nuclear force
E) attract electrons electrically
Q:
Which one of the following represents a fusion reaction that would yield large amounts of energy?
Q:
To produce energy by fusion of two nuclei, the nuclei must:
A) have at least several thousand electron volts of kinetic energy
B) both be above iron in mass number
C) have more neutrons than protons
D) be unstable
E) be magic number nuclei
Q:
The binding energy per nucleon:
A) increases from all fusion events
B) increases for some, but not all, fusion events
C) remains the same for some fusion events
D) decreases for all fusion events
E) decreases for some, but not all, fusion events