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
• What are nucleons?

  Protons and neutrons
• How do electrons behave 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
• How is specific charge calculated?

  Charge divided by mass

  
• What is the specific charge of a proton?

  9.58 × 10⁷ Ckg⁻¹

  
• What does the proton number (Z) represent?

  Number of protons in an atom
• What does the nucleon number (A) represent?

  Number of protons and neutrons
• What are isotopes?

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

  Carbon dating of organic materials
• What is the strong nuclear force (SNF)?

  Force that stabilizes the nucleus
• What does the strong nuclear force counteract?

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

  Short range, up to 3 fm
• What happens to unstable nuclei?

  They decay to become stable
• What is alpha decay?

  Decay in large nuclei with excess nucleons
• What changes occur during alpha decay?

  Proton number decreases by 2, nucleon number by 4
• What is beta-minus decay?

  Decay in neutron-rich nuclei

  
• What changes occur during beta-minus decay?

  Proton number increases by 1, nucleon number stays the same

  
• Why were neutrinos hypothesized?

  To account for energy not conserved in beta decay
• What is an antiparticle?

  Particle with opposite properties to a particle
• What is the relationship between a particle and its antiparticle?

  Same mass and rest energy, opposite properties
• What is the charge of a positron?

  +1.6 × 10⁻¹⁹ C
• What are photons?

  Massless packets of electromagnetic radiation
• How is the energy of photons related to frequency?

  Energy is directly proportional to frequency
• What is the equation for photon energy?

  E = hf
• What is annihilation in particle physics?

  Collision of particle and antiparticle converting mass to energy
• What is the result of annihilation?

  Release of energy as photons
• How does a PET scanner work?

  Uses positron emission to create images
• What is pair production?

  Photon converted into matter and antimatter
• What is required for pair production to occur?

  Photon energy greater than total rest energy
• What are the four fundamental forces?

  • Gravity
  • Electromagnetic
  • Weak nuclear
  • Strong nuclear
• What causes forces between particles?

  Exchange particles carrying energy and momentum
• What is the range of the weak nuclear force?

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

  Indicates if it is a lepton or not
• What is the baryon number of a particle?

  Indicates if it is a baryon or not
• What are the exchange particles for each fundamental force?

  • Strong: Gluon
  • Weak: W boson
  • Electromagnetic: Virtual photon
  • Gravity: Graviton (not specified)
• What is a muon?

  A heavy electron that decays into electrons