• Created by: Epic Al
  • Created on: 03-07-22 12:57
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  • Radioactivity
    • atoms and decay
      • alpha
        • single hydrogen ion
          • -4 atomic mass -2 proton number
      • beta
        • single electron
          • +1 proton number
      • gamma
        • waves
      • Decay is random
    • Particles
      • alpha
        • stopped by paper
        • stopped in a few cm of air
        • 2 protons 2 neutrons
      • beta
        • stopped by a thin sheet of metal
        • stopped after about 1m in air
        • less ionising than alpha
      • gamma
        • stopped by thick lead
        • unlimited range in air
        • electromagnetic radiation
      • ionisation in living cells can kill the cell
    • activity and half-life
      • half life is the time it takes for the nuclei in the sample to halve
      • count rate after n half lives = initial count rate / 2^n
    • radiation in medicine
      • imaging and treating caner
      • usefulness depends on half life and type of radiation
      • for medical imaging half life should be not too long but not too short
      • gamma beam or radioactive implant can destroy cancer cells
    • nuclear fission
      • splitting of an atoms nucleus releasing energy
      • a chain reaction occurs in a nuclear reactor when each fission event causes more fission events
      • control rods absorb fission neutrons to ensure there are no chain reactions
    • nuclear fusion
      • forcing 2 nuclei together so they form a larger nucleus
      • making 2 light nuclei collide at a very high age
      • energy is released like in the suns core
      • needs to be a very high temperature
    • nuclear issues
      • radon gas can seep into houses through the ground
      • hundred of fission reactors around the world
      • nuclear waste emits radiation for many years
      • nuclear waste is stored safely for many years


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