76. Annihilation in the early universe produced:
- a huge number of photons
- more antimatter
- black holes only
- the Moon
Answer: A) a huge number of photons
Explanation: About 10^9 photons per baryon today. SLO P-11-F-26 · Knowledge
MCQs / Physics / Nuclear and Particle Physics
Nuclear and Particle Physics MCQs — Physics (page 4)
330 multiple-choice questions on Nuclear and Particle Physics from Physics, each with the correct answer and, where available, a teacher's explanation. Read through them to revise the chapter, then practise the same questions one by one to test yourself.
77. Experiments at CERN (ALPHA-g, 2023) showed that antihydrogen:
- falls downward under gravity like ordinary matter
- falls upward
- floats
- is weightless
Answer: A) falls downward under gravity like ordinary matter
Explanation: Same gravitational behaviour. SLO P-11-F-25 · Understanding
78. Gluons carry a property called:
- colour charge
- mass charge
- flavour
- electric charge
Answer: A) colour charge
Explanation: They interact with each other too. SLO P-11-F-17 · Knowledge
79. Neutrinos have:
- no charge and almost zero mass
- a positive charge
- a negative charge
- a large mass
Answer: A) no charge and almost zero mass
Explanation: Very weakly interacting. SLO P-11-F-10 · Knowledge
80. Which property would distinguish a neutron from an antineutron?
- its charge
- its weight
- its mass
- the direction of its magnetic moment (and baryon number)
Answer: D) the direction of its magnetic moment (and baryon number)
Explanation: Both are neutral. SLO P-11-F-25 · Understanding
81. Gluons are the exchange particles for the:
- gravitational force
- electromagnetic force
- strong force
- weak force
Answer: C) strong force
Explanation: Hold quarks together. SLO P-11-F-17 · Knowledge
82. An antiparticle has the same mass as its particle but:
- the same charge
- double the charge
- zero mass
- opposite charge and other quantum numbers
Answer: D) opposite charge and other quantum numbers
Explanation: e.g. opposite magnetic moment. SLO P-11-F-19 · Understanding
83. How many up quarks are in a neutron?
- 0
- 1
- 2
- 3
Answer: B) 1
Explanation: udd. SLO P-11-F-20 · Understanding
84. A particle with quark content barubarubard is:
- a meson
- a baryon
- a lepton
- an antibaryon (antiproton)
Answer: D) an antibaryon (antiproton)
Explanation: Three antiquarks. SLO P-11-F-21 · Knowledge
85. The charge of a proton can be checked from its quarks as:
- 23 3 = 2
- 23 + 23 - 13 = 1
- - 13 3 = -1
- 23 - 13 - 13 = 0
Answer: B) 23 + 23 - 13 = 1
Explanation: In units of e. SLO P-11-F-20 · Understanding
86. A Lambda^0 particle (uds) is:
- a baryon with charge +e
- a baryon with zero charge
- a meson with zero charge
- a lepton
Answer: B) a baryon with zero charge
Explanation: 23 - 13 - 13 = 0. SLO P-11-F-21 · Knowledge
87. Quarks are considered:
- fundamental particles (not made of smaller particles)
- made of electrons
- composite particles
- made of protons
Answer: A) fundamental particles (not made of smaller particles)
Explanation: Standard Model. SLO P-11-F-12 · Understanding
88. The boson involved in beta^+ decay is the:
- W^+
- photon
- W^-
- Z^0
Answer: A) W^+
Explanation: u to d + W^+, then W^+ to e^+ + nue. SLO P-11-F-15 · Knowledge
89. Antimatter and matter have:
- different gravity sign
- opposite mass
- no relation
- the same mass
Answer: D) the same mass
Explanation: Experiments support same gravitational behaviour. SLO P-11-F-24 · Understanding
90. If an antiproton and a proton are placed at rest a short distance apart, they will:
- repel each other
- exert no force
- move apart
- attract each other electrically
Answer: D) attract each other electrically
Explanation: Opposite charges. SLO P-11-F-25 · Understanding
91. A nucleus ^22688 Ra emits an alpha particle. The daughter nucleus has nucleon number A and proton number Z:
- A = 226, Z = 88
- A = 226, Z = 84
- A = 224, Z = 87
- A = 222, Z = 86
Answer: D) A = 222, Z = 86
Explanation: Nucleon number and charge are conserved: daughter ^22286X. SLO P-11-F-07 · Knowledge
92. The CP violation observed so far is:
- zero
- exactly enough
- too small to explain the observed asymmetry
- too large
Answer: C) too small to explain the observed asymmetry
Explanation: Hence the mystery. SLO P-11-F-27 · Understanding
93. A kaon K^+ has quark composition ubars. It is a:
- baryon
- meson
- lepton
- gauge boson
Answer: B) meson
Explanation: Quark + antiquark. SLO P-11-F-21 · Knowledge
94. The magnetic moment of an antiparticle is:
- doubled
- opposite to that of its particle
- the same
- zero
Answer: B) opposite to that of its particle
Explanation: Opposite magnetic properties. SLO P-11-F-19 · Understanding
95. Which combination of three quarks has charge +2e?
- ddd
- uuu
- uud
- udd
Answer: B) uuu
Explanation: The Delta^++ baryon. SLO P-11-F-13 · Understanding
96. A nucleus ^23892 U emits an alpha particle. The daughter nucleus has nucleon number A and proton number Z:
- A = 236, Z = 91
- A = 238, Z = 92
- A = 234, Z = 90
- A = 238, Z = 88
Answer: C) A = 234, Z = 90
Explanation: Nucleon number and charge are conserved: daughter ^23490X. SLO P-11-F-07 · Knowledge
97. Charge conservation in beta^- decay requires that:
- the nucleus loses a proton
- the electron comes from the atom's shell
- a neutron becomes a proton and an electron
- a proton becomes a neutron
Answer: C) a neutron becomes a proton and an electron
Explanation: 0 = +1 + (−1). SLO P-11-F-07 · Knowledge
98. Bottom quarks have charge:
- 0
- + 23e
- - 13e
- -e
Answer: C) - 13e
Explanation: Same as down. SLO P-11-F-12 · Understanding
99. A beta^+ particle is:
- a neutron
- a proton
- an electron
- a positron (anti-electron)
Answer: D) a positron (anti-electron)
Explanation: Charge +e, same mass as an electron. SLO P-11-F-08 · Understanding
100. The antiproton has:
- twice the proton's charge
- the mass of a proton and a negative charge
- no charge
- the mass of an electron and a positive charge
Answer: B) the mass of a proton and a negative charge
Explanation: Antiparticle of the proton. SLO P-11-F-09 · Understanding
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