Types of Radiation

• What model of the atom is currently accepted?

  Nuclear model
• What does the nuclear model describe about atoms?

  Atoms consist of a central nucleus and orbiting electrons

  
• What is the relative charge of a neutron?

  0
• What are isotopes?

  Same element has same number of protons but different numbers of neutrons in the nuclei
• How do isotopes of an element differ?

  They have different mass numbers
• Which Hydrogen isotope is the most stable?

  H-1
• What are the three main types of radioactive emission?

  Alpha, Beta, Gamma

  
• What is emitted during alpha decay?

  Alpha particles
• What is an alpha particle equivalent to?

  A helium nucleus
• What can stop alpha radiation?

  Thin paper
• What type of particle is emitted during beta decay?

  Beta particles

  
• What is the charge of a beta particle?

  -1
• What can stop beta radiation?

  Thin metal
• What type of radiation is gamma radiation?

  Electromagnetic radiation
• What is the speed of gamma radiation?

  Speed of light
• What is required to stop gamma radiation?

  A thick lead block
• What does the random nature of radioactive decay imply?

  Specific atoms cannot be predicted to decay
• What is a half-life?

  Time taken to halve number of radioactive atoms
• How can half-life be found?

  Experimentally with repeat readings
• What are the two types of radiation sources?

  Natural and man-made
• What is the biggest contributor to background radiation?

  Rocks and buildings
• How long can high-level waste take to decay to safer levels?

  Thousands of years
• What makes an isotope unstable

  Imbalance between number of protons and neutrons in the nucleus
• How random decay is accounted for

  Repeat readings to be made preferably measurements over a lengthy period.
• Rank types of radiation of penetrating power and range

  Gamma > Beta > Alpha
• Rank types of radiation of ionising ability

  Alpha > Beta > Gamma
• How does nuclear fission occur

  Slow moving neutrons are absorbed by heavy U -235 nuclei during collisions releasing fast moving neutrons
• Functions of moderator and control rods

  Moderator - slows down fast moving neutrons to enable absorption by u-235 nuclei to occur

  Control rods - arranged to absorb neutrons so that every 2 or 3 neutrons that are released from fission reactions
• How is a nuclear fission reactor shut down

  lower control rods completely
• What is nuclear fission

  2 light nuclei collide and fuse producing helium and releasing energy
• Conditions for nuclear fission

  Requires very high temperatures and pressures