4.4 Nuclear Fission & Fusion

• What is nuclear fission?

  The splitting of a large nucleus
• What happens during nuclear fission?

  A large nucleus splits into smaller nuclei

  
• Which isotopes are commonly used in nuclear fission?

  Uranium and plutonium
• What occurs when a neutron collides with an unstable nucleus during fission?

  The nucleus splits and emits neutrons

  
• What are daughter nuclei?

  The smaller nuclei produced from fission

  
• What type of energy is transferred during fission?

  Nuclear potential energy to kinetic energy
• What is spontaneous fission?

  Fission without additional energy input
• What is induced fission?

  Fission initiated by neutron absorption
• What is the half-life of uranium-235?

  700 million years
• Why is uranium-235 unsuitable for immediate energy production?

  It has low activity and releases energy slowly
• What happens to uranium-236 after neutron absorption?

  It splits almost immediately by fission

  
• What is a chain reaction in nuclear fission?

  A series of fission reactions initiated by neutrons

  
• How does a chain reaction start with uranium-235?

  One neutron induces the nucleus to split

  
• What role do control rods play in a nuclear reactor?

  They absorb neutrons to control the reaction
• What can happen during uncontrolled chain reactions?

  They can lead to dangerous explosions
• What is the purpose of diagrams in nuclear fission?

  To illustrate the fission process clearly

  
• What is nuclear fusion?

  When two light nuclei join to form a heavier nucleus
• Where does nuclear fusion occur naturally?

  In the centers of stars
• What is the energy source during nuclear fusion?

  A small amount of mass converted into energy
• What is the mass-energy equivalence equation?

  E = m × c
• What does the variable 'c' represent in the mass-energy equation?

  The speed of light in m/s
• How much energy does 1 kg of hydrogen produce during fusion?

  Equivalent to burning 10 million kg of coal
• Why is hydrogen fusion not currently possible on Earth?

  It requires extremely high temperatures
• What force must be overcome for hydrogen nuclei to fuse?

  The repulsive force between positive charges
• What is the product of hydrogen fusion?

  Helium

  
• Why is helium considered an inert gas?

  It does not readily react with other elements