Particles and Radiation

• What are the three constituents of an atom?

  Protons, neutrons, and electrons
• What forms the nucleus of an atom?

  Protons and neutrons
• How do electrons move in an atom?

  They orbit the nucleus in shells
• What properties of particles can be described in SI and relative units?

  • Charge (C)
  • Relative Charge
  • Mass (kg)
  • Relative Mass
  • Specific Charge (Ckg^-1)
• What is the charge of a proton in coulombs?

  +1.6 × 10⁻¹⁹ C
• What is the mass of a neutron in kilograms?

  1.67 × 10⁻²⁷ kg
• What is specific charge?

  Charge-mass ratio of a particle

  
• How is specific charge calculated?

  Charge divided by mass

  
• What is the proton number denoted by?

  Z
• What is the nucleon number denoted by?

  A
• What are isotopes?

  Atoms with the same protons, different neutrons
• What is carbon-14 used for?

  Carbon dating of organic materials
• What does carbon dating involve?

  Calculating remaining carbon-14 percentage
• What keeps nuclei stable?

  The strong nuclear force (SNF)
• What does the strong nuclear force counteract?

  Electrostatic force of repulsion
• What is the range of the strong nuclear force?

  Attractive up to 3 fm, repulsive below 0.5 fm
• What causes unstable nuclei to decay?

  Too many protons, neutrons, or both
• What occurs during alpha decay?

  Proton number decreases by 2
• What occurs during beta-minus decay?

  Proton number increases by 1
• What was hypothesized to account for energy conservation in beta decay?

  Neutrinos
• What is an antiparticle?

  Particle with opposite properties
• What is the mass of an electron?

  9.11 × 10^−31 kg
• What is the charge of a positron?

  +1.6 × 10⁻¹⁹ C
• What do photons transfer?

  Energy
• How is the energy of photons related to frequency?

  Directly proportional
• What happens during annihilation?

  Mass is converted into energy
• How does a PET scanner work?

  Detects gamma photons from annihilation
• What is pair production?

  Photon converts into matter and antimatter
• What are the four fundamental forces?

  Gravity, electromagnetic, weak nuclear, strong nuclear
• What causes forces between particles?

  Exchange particles
• What are the exchange particles for the fundamental forces?

  • Strong: Gluon
  • Weak: W boson
  • Electromagnetic: Virtual photon
  • Gravity: Graviton (not specified)
• What is the range of the weak nuclear force?

  10⁻¹⁸ m
• What is the lepton number of a lepton?

  1
• What is the baryon number of a baryon?

  1
• What is the lepton number of an antilepton?

  -1
• What is the strangeness of a strange particle?

  -1
• What is the decay process of a muon?

  Muons decay into electrons
• What is the significance of conservation laws in particle interactions?

  They must always be conserved
• What properties must always be conserved in particle interactions?

  • Energy and momentum
  • Charge
  • Baryon number
  • Lepton number
• What is the charge of a down quark?

  −1/3 e