Particles, Antiparticles and Photons

• What does the Universe consist of in terms of matter?

  Particles like protons, neutrons, electrons
• What is the relationship between particles and antiparticles?

  Each particle has an antimatter counterpart
• How do antimatter particles differ from their matter counterparts?

  They have opposite charges

  
• What prefix is used for the name of an antiparticle?

  Anti-
• What properties do corresponding matter and antimatter particles share?

  Same mass and rest mass-energy

  
• What is the definition of rest mass-energy?

  Energy equivalent to mass at rest
• What are photons?

  Fundamental particles of electromagnetic radiation
• How is energy transferred by photons?

  As discrete packets of energy
• What is the formula to calculate photon energy?

  E = hf
• How does photon energy relate to frequency?

  Higher frequency means higher energy
• What is the relationship between photon energy and wavelength?

  Energy is inversely proportional to wavelength
• What is the minimum energy of one photon after annihilation?

  Total rest mass energy of one particle
• What happens during annihilation?

  Particle and antiparticle are destroyed
• What are the two common particle-antiparticle pairs?

  Proton-antiproton and electron-positron
• What is pair production?

  Creation of a particle-antiparticle pair from a photon
• What is the minimum energy required for pair production?

  Total rest mass energy of the particles produced
• How do particles and antiparticles move after pair production?

  They move apart in opposite directions
• What must a photon have to create a particle-antiparticle pair?

  Enough energy to create both particles
• How is momentum conserved in annihilation and pair production?

  Photons move apart in opposite directions
• What is the formula for the minimum energy of one photon after annihilation?

  Emin = hf min = E
• What is the formula for the minimum energy required for pair production?

  Emin = hf min = 2E
• What should you remember about the Planck constant in calculations?

  It is in Joules (J)
• How do you calculate the maximum wavelength of photons produced in annihilation?

  Use energy and Planck's constant