Physics Mind Map
 
 
 
 

Physics - Mind Map

3 years ago by: Aiman Khair
 
 
physics p6
  • Physics
    • Structure Of Atoms
      • Atomic nuclei are made of protons and neutrons
      • Same element may have different amount of neutrons
      • Isotope is a charged atom
        • May have more or less electrons
    • Types Of Radiation
      • Alpha
        • Mass
          • Heaviest
        • Range
          • 5cm
        • Penetrating power
          • Paper/skin
        • Ionising power
          • Very strong
      • Beta
        • Mass
          • 1/2000
        • Range
          • Many metres
        • Penetrating power
          • 1cm of aluminium
        • Ionising power
          • Weak
      • Gamma
        • Mass
          • No mass
        • Range
          • Air has no effect
        • Penetrating power
          • Reduced by many meters of concrete
          • Cannot be stopped completely
        • Ionising power
          • Minimal
    • Fission
      • Larger atoms split to form more stable daughter atoms nuclei which have kinetic energy
      • Lots of energy is also released in form of gamma radiation
      • Can happen spontaneuosly
      • can be invoked if nucleus absorbs an electron
      • Examples include uranium and plutonium
      • Used to generate elctricity
        • Nuclear reaction using uranium
        • Energy is released
        • Used to heat water and make steam
        • Turns a turbine
        • Turns a generator to make electricity
        • Advantages and disadvantages
          • Advantages
            • Lots of energy released
            • No C02 is released
          • Disadvantages
            • Nuclear waste is radioactive and has a very long half life
            • Very expensive to decomission
            • of radiation leak
    • Fusion
      • Joining of smaller nuclei
      • Happens in stars
      • Mass may be converted to radiation
      • Total mass of products is less than reactants and energy released
      • 2 protons have same charge so they repel
        • Need high temperatures and pressures
      • No radioactive waste
    • Half life
      • Time taken for half of the radioactive atoms to decay
      • Can be millions of years or under a second
    • Electron energy leves
      • In each atom electrons are arranged at different distances
        • May change with absorption or emission
          • Atom becomes an ion
      • Inner electrons can be 'excited' when they absorb energy from radiation and go to a higher energy level
      • Changes in atoms and nuclei can also generate and absorb radiations over a wide frequency range
        • From any part of EM spectrum
      • Ionization is when an outer shell electron is removed due to radiation
    • Uses and hazards
      • Contamination and irradiation
        • contamination
          • radioactive material is swallowed or breathed in. While inside the body it causes damage
        • Irradiation
          • Radiation from outside damages the bodies cells
      • Radiation can damage cells and cause cancer
      • Typical half life for a tracer is 3 hours
      • Gamma ray scans
        • A gamma ray emitter is placed in a collimater so it emits a thin mean of gamma rays
        • This is directed at the tumor from different angles
        • surrounding cells get a smaller cell than tumor
        • Cells in the tumor are killed
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