AQA P2.6.txt

  1. Name two substances that are commonly used as fuel in nuclear fission reactors
    • uranium-235
    • plutonium-239
  2. What is the name of the process whereby a nucleus is split into smaller parts
    Nuclear fission
  3. Which particle must be absorbed by uranium-235 or plutonium-239 for fission to occur?
    A neutron
  4. What is produced when an unstable nucleus splits into two smaller nuclei?
    Energy, and 2 or 3 neutrons
  5. What is nuclear fusion?
    The joining of two atomic nuclei to form a larger one
  6. What is the name of the process by which energy is released in stars?
    Nuclear fusion
  7. What force pulls together dust and gas within nebulae?
  8. What is the name given to the stable part of a star's lifecycle?
    Main sequence
  9. What determines the lifecycle path of a star?
    Its size
  10. Where are elements up to the mass of iron formed?
    By a star in its stable period
  11. How are all the naturally occurring elements produced?
    By fusion processes (either during a stars main sequence or during a supernova at the end of its life)
  12. What name is given to a star before it starts its main sequence?
  13. What is left at the end of the biggest stars life?
    Black hole
  14. What does a star the same size as the Sun become immediately after its main sequence?
    Red Giant
  15. Put these into the correct sequence for a star like our sun:
      white dwarf 
      black dwarf 
      red giant
      main sequence
    • Nebula => protostar => main sequence =>
    • red giant => white dwarf => black dwarf
    • Image Upload 1
  16. What is a supernova?
    An explosion at the end of the life of a large star
  17. What is the role of the moderator in a fission reactor?
    It slows down the neutrons so that they are slow enough to be absorbed by nuclei (and so continue the chain reaction)
  18. How is a nuclear fission reactor controlled?
    By the use of control rods which can be inserted to absorb neutrons and so slow down the chain reaction
  19. Why is nuclear fusion hard to achieve?
    The positively charged nuclei will repel each each other and overcoming this requires a large amount of energy.
  20. How are planets formed?
    Matter from a protostar may not all become part of the star. The remainder will eventually be drawn together by gravity to form planets, moons, asteroids and comets.
  21. The most common fuel in the sun is Hydrogen. Which two isotopes of hydrogen fuse to form Helium?
    • Deuterium
    • Tritium
Card Set
AQA P2.6.txt
AQA Physics 2.6 Fission and Fusion