Particles and radiation

• What are the three constituents of an atom?

  Protons, neutrons, and electrons
• Where are protons and neutrons located in an atom?

  In the nucleus
• What are protons and neutrons collectively known as?

  Nucleons
• How do electrons move in relation to the nucleus?

  Electrons orbit the nucleus in shells
• What are the properties of protons, neutrons, and electrons in terms of charge and mass?

  • Proton: Charge = +1.6 × 10⁻¹⁹ C, Mass = 1.67 × 10⁻²⁷ kg
  • Neutron: Charge = 0 C, Mass = 1.67 × 10⁻²⁷ kg
  • Electron: Charge = −1.6 × 10⁻¹⁹ C, Mass = 9.11 × 10⁻³¹ kg
• What is specific charge and how is it calculated?

  Specific charge is the charge-mass ratio calculated by dividing a particle's charge by its mass

  
• What is the specific charge of a proton?


  $9.58 \times 10^7 \text{ Ckg}^{-1}$
• What does the proton number (Z) represent in an atom?

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

  The total number of protons and neutrons in an atom
• What are isotopes?


  Atoms with the same number of protons but different numbers of neutrons
• How is carbon-14 used in carbon dating?

  By calculating the percentage of carbon-14 remaining in an object
• What is the strong nuclear force (SNF)?

  A force that keeps nuclei stable by counteracting the electrostatic force of repulsion between protons
• What happens to unstable nuclei?

  They decay to become stable
• What type of decay occurs in large nuclei with too many protons and neutrons?

  Alpha decay
• What occurs during alpha decay?

  The proton number decreases by 2 and the nucleon number decreases by 4
• What type of decay occurs in neutron-rich nuclei?

  Beta-minus decay
• What happens during beta-minus decay?

  The proton number increases by 1 while the nucleon number stays the same
• Why were neutrinos hypothesized during beta-minus decay observations?

  To account for the missing energy that was not conserved
• What is an antiparticle?

  A particle that has the same rest energy and mass but opposite properties
• What is the relationship between photons and electromagnetic radiation?

  Photons are packets of electromagnetic radiation that transfer energy
• How is the energy of a photon related to its frequency?

  The energy of photons is directly proportional to the frequency of electromagnetic radiation
• What is annihilation in particle physics?

  The collision of a particle and its antiparticle resulting in their masses being converted into energy
• What is the result of annihilation?

  Energy is released in the form of two photons moving in opposite directions
• How does a PET scanner utilize annihilation?

  By introducing a positron-emitting radioisotope that annihilates with electrons, emitting gamma photons
• What is pair production?

  The conversion of a photon into an equal amount of matter and antimatter
• What are the four fundamental forces in particle physics?

  Gravity, electromagnetic, weak nuclear, and strong nuclear
• What are exchange particles?

  Particles that carry energy and momentum between particles experiencing a force
• What are the exchange particles for the four fundamental forces?

  • Strong: Gluon
  • Weak: W boson (W⁺, W⁻)
  • Electromagnetic: Virtual photon (γ)
  • Gravity: Graviton (not on specification)
• What is the role of the weak nuclear force?

  It is responsible for beta decay, electron capture, and electron-proton collisions
• How do the equations for electron capture and electron-proton collision compare?

  They are the same but use different exchange particles
• What are hadrons and leptons?

  Hadrons are particles made of quarks, while leptons are fundamental particles that cannot be broken down
• What is the baryon number of a particle?


  A number that indicates whether a particle is a baryon (1), antibaryon (-1), or not a baryon (0)
• What is the lepton number of a particle?


  A number that indicates whether a particle is a lepton (1), antilepton (-1), or not a lepton (0)
• What is a muon?

  A particle sometimes known as a "heavy electron" that decays into electrons
• What are strange particles?

  Particles produced by the strong nuclear interaction that decay by the weak interaction
• What is strangeness in particle physics?


  A property of particles indicating that strange particles must be created in pairs
• How does strangeness behave in strong and weak interactions?

  In strong interactions, strangeness must be conserved; in weak interactions, it can change by 0, +1, or -1
• Why are particle accelerators built?

  To investigate particle physics
• What is the challenge associated with particle accelerators?

  They are expensive to build and run, and produce huge amounts of data
• What are quarks?


  Fundamental particles that make up hadrons