31.2 Matter and Antimatter
1. A proton and antiproton each with total energy 800 GeV collide head-on. What is the total
energy (particles + energy) released?
a. zero b. 800 GeV
c. 400 GeV d. 1600 GeV
ANSWER: d
2. The exchange of mediating photons can produce
a. neither a repulsive nor an attractive force.
b. either a repulsive or an attractive force.
c. a repulsive force.
d. an attractive force.
ANSWER: b
3. Which of these particles has the least mass?
a. electron neutrino b. muon
c. electron d. pion
ANSWER: a
4. What following quantity is conserved in the following reaction: ?
a. charge b. lepton number
c. baryon number d. All of the above.
ANSWER: d
31.4 Elementary Particle Physics: The Standard Model
5. If a K0 meson at rest decays in 0.90 × 10−10 s, how far will a K0 meson moving at 0.95c travel
,through a bubble chamber? (c = 3.00 × 108 m/s)
a. 2.6 cm b. 8.2 cm
c. 9.3 cm d. 13 cm
ANSWER: b
6. Of the quarks u, d, c, s, t, and b, which have positive fractional electronic charge?
a. u, d, c b. d, s, b
c. s, t, b d. u, c, t
ANSWER: d
7. The constituent quarks of the proton are uud. What are the charges on u and d?
a. b.
c. d.
ANSWER: a
8. Of the following mesons, which is its own antiparticle?
a. K– b. φ
c. π+ d. none of those given
ANSWER: b
9. Which of the following forces is the strongest at near distances?
a. gravitational b. weak nuclear
c. strong nuclear d. electromagnetic
ANSWER: c
10. The following reaction can occur by the strong interaction: π0 + n → K+ + Σ–. If the quark
composition of the n is (udd), the π 0 is and the composition of the K+ is , what is the
quark composition of the Σ–?
, a. uds b. dds
c. sss d.
ANSWER: b
11. The strong force is mediated by
a. the gluon. b. the W– boson.
c. the W+ boson. d. All of these choices.
ANSWER: a
12. Processes in which one type of quark is converted into another type of quark involve which
force?
a. electromagnetic b. strong force
c. weak force d. gravitational
ANSWER: c
13. The quark structure of the neutron is udd. What is the quark structure of the antineutron?
a.
b. ddu
c.
d. udd, since the neutron is its own antiparticle
ANSWER: a
31.7 Astrophysics and the Universe
14. The cosmic background radiation appears compatible with a blackbody source at what
temperature?
a. 0.0003 K b. 3 K
c. 300 K d. 0.03 K
, ANSWER: b
15. The microwave background radiation:
a. represents the leftover glow from the Big Bang.
b. had its slight non-uniformity measured by COBE.
c. was discovered by Penzias and Wilson.
d. All of the above.
ANSWER: d
16. Assuming the Hubble constant is (21 km/s)/(106 ly), what is the recession speed of a galaxy
300 million parsecs away? (1 parsec = 3.26 ly)
a. 4200 km/s b. 21,000 km/s
c. 640 km/s d. 7000 km/s
ANSWER: b
1. Since 1983 the standard meter has been defined in terms of which of the following?
a. specific alloy bar housed at Sevres, France
b. wavelength of light emitted by krypton-86
c. distance from the Earth's equator to the North Pole
d. the distance light travels in a certain fraction of a second
e. None of the above
ANSWER: d
2. Since 1967 the standard definition for the second has been based on which of the following?
a. characteristic frequency of the cesium-133 atom
1. A proton and antiproton each with total energy 800 GeV collide head-on. What is the total
energy (particles + energy) released?
a. zero b. 800 GeV
c. 400 GeV d. 1600 GeV
ANSWER: d
2. The exchange of mediating photons can produce
a. neither a repulsive nor an attractive force.
b. either a repulsive or an attractive force.
c. a repulsive force.
d. an attractive force.
ANSWER: b
3. Which of these particles has the least mass?
a. electron neutrino b. muon
c. electron d. pion
ANSWER: a
4. What following quantity is conserved in the following reaction: ?
a. charge b. lepton number
c. baryon number d. All of the above.
ANSWER: d
31.4 Elementary Particle Physics: The Standard Model
5. If a K0 meson at rest decays in 0.90 × 10−10 s, how far will a K0 meson moving at 0.95c travel
,through a bubble chamber? (c = 3.00 × 108 m/s)
a. 2.6 cm b. 8.2 cm
c. 9.3 cm d. 13 cm
ANSWER: b
6. Of the quarks u, d, c, s, t, and b, which have positive fractional electronic charge?
a. u, d, c b. d, s, b
c. s, t, b d. u, c, t
ANSWER: d
7. The constituent quarks of the proton are uud. What are the charges on u and d?
a. b.
c. d.
ANSWER: a
8. Of the following mesons, which is its own antiparticle?
a. K– b. φ
c. π+ d. none of those given
ANSWER: b
9. Which of the following forces is the strongest at near distances?
a. gravitational b. weak nuclear
c. strong nuclear d. electromagnetic
ANSWER: c
10. The following reaction can occur by the strong interaction: π0 + n → K+ + Σ–. If the quark
composition of the n is (udd), the π 0 is and the composition of the K+ is , what is the
quark composition of the Σ–?
, a. uds b. dds
c. sss d.
ANSWER: b
11. The strong force is mediated by
a. the gluon. b. the W– boson.
c. the W+ boson. d. All of these choices.
ANSWER: a
12. Processes in which one type of quark is converted into another type of quark involve which
force?
a. electromagnetic b. strong force
c. weak force d. gravitational
ANSWER: c
13. The quark structure of the neutron is udd. What is the quark structure of the antineutron?
a.
b. ddu
c.
d. udd, since the neutron is its own antiparticle
ANSWER: a
31.7 Astrophysics and the Universe
14. The cosmic background radiation appears compatible with a blackbody source at what
temperature?
a. 0.0003 K b. 3 K
c. 300 K d. 0.03 K
, ANSWER: b
15. The microwave background radiation:
a. represents the leftover glow from the Big Bang.
b. had its slight non-uniformity measured by COBE.
c. was discovered by Penzias and Wilson.
d. All of the above.
ANSWER: d
16. Assuming the Hubble constant is (21 km/s)/(106 ly), what is the recession speed of a galaxy
300 million parsecs away? (1 parsec = 3.26 ly)
a. 4200 km/s b. 21,000 km/s
c. 640 km/s d. 7000 km/s
ANSWER: b
1. Since 1983 the standard meter has been defined in terms of which of the following?
a. specific alloy bar housed at Sevres, France
b. wavelength of light emitted by krypton-86
c. distance from the Earth's equator to the North Pole
d. the distance light travels in a certain fraction of a second
e. None of the above
ANSWER: d
2. Since 1967 the standard definition for the second has been based on which of the following?
a. characteristic frequency of the cesium-133 atom
