Particles

• How do you calculate specific charge?

  Charge / Mass
• What is an isotope?

  An isotope is a variant of an element that has the same number of protons but a different number of neutrons
• What is isotopic data?


  The relative amounts of different isotopes of an element found within a substance
• Why are isotopes unstable?

  Neutron-proton imbalance
• Use of isotopic data:

  • All living things have the same ratio of Carbon-14 to Carbon-12
  • After death Carbon- 14 decays
  • Scientists can use the percentage left and compare this with data, to calculate the age of the sample
  • This is called carbon dating
• Why is the strong force repulsive below 0.5 fm?

  To prevent the nucleus from collapsing to a point
• Why is the strong force attractive between 0.5-3 fm?

  To balance out the electrostatic repulsion between protons in the nucleus
• After what distance is the strong force negligible?

  3 fm
• At what distance of separation is the strong force attractive?

  0.5 - 3 fm
• At what distance of separation is the strong force repulsive?

  Below 0.5 fm
• Why may a nuclei be unstable?

  Unbalanced forces
• What is alpha radiation?

  Helium nucleus
• What does a helium nuclei consist of?

  2 protons

  2 neutrons
• Alpha radiation is highly ionising and weakly penetrating
• Alpha decay is stopped by 1-5 cm of air
• How do alpha particles travel in cloud chambers?

  Short, straight lines
• How does beta minus decay occur?

  A neutron turns into a proton, emitting an electron and an electron antineutrino
• How does beta plus decay occur?

  A proton turns into a neutron, emitting a positron and an electron neutrino
• The existence of the neutrino was hypothesised to account for conservation of energy in beta decay
• A beta particle is stopped by 2 mm of alumnium
• What is gamma radiation?

  A high energy electromagnetic wave
• Gamma radiation is stopped by lead
• Atomic Structure

  A) electron

  B) proton

  C) neutron

  D) -15

  E) -10

  
• Nuclide Notation

  A) nucleon

  B) proton

  
• Fundamental Forces

  A) charged

  B) virtual photon

  C) all

  D) graviton

  E) all

  F) W

  G) W

  H) Z

  I) hadrons

  J) pion

  
• Strong Nuclear Force

  A) 0.5

  B) 3

  
• Alpha Decay

  A) A-4

  B) Z-2

  C) 4

  D) 2

  
• Beta Minus Decay

  A) A

  B) Z+1

  C) 0

  D) -1

  E) 0

  F) 0

  
• Beta Plus Decay

  A) A

  B) Z-1

  C) 0

  D) 1

  E) 0

  F) 0

  
• The existence of the neutrino

  • The same amount of energy is released in each decay
  • When the energy is less than the maximum there is missing energy
  • Total energy of the beta particle and nucleus are not constant
  • There must be another particle to carry away missing energy

  
• For every type of particle there is a corresponding antiparticle
• Antiparticles have opposite quantum properties to their particle counterparts
• What do particles and their corresponding antiparticles have in common?

  Rest mass

  Rest energy
• What is the antiparticle of a proton?

  Antiproton
• What is the antiparticle of a neutron?

  Antineutron
• What is the antiparticle of an electron?

  Positron
• What is the antiparticle of a neutrino?

  Antineutrino
• Energy = Planck's constant (h) x frequency
• Energy = (Planck's Constant x speed of light) / wavelength
• What is annihilation?

  When a particle collides with its own antiparticle. All mass is converted into energy in the form of two photons travelling in opposite directions to conserve momentum