Nuclear Fusion and Fission

• What is nuclear fusion defined as?

  The fusing of two small nuclei
• Which types of nuclei can undergo fusion?

  Low mass nuclei like hydrogen and helium
• What element is produced when two protons fuse?

  Deuterium

  
• What happens to deuterium in the center of stars?

  It combines with tritium to form helium

  
• What is released when deuterium and tritium fuse?

  Energy

  
• What is required for two nuclei to fuse?

  Both must have high kinetic energy
• Why is it difficult for nuclei to fuse?

  Due to electrostatic repulsion and strong nuclear force
• What causes electrostatic repulsion in nuclei?

  Positively charged protons
• What is the strong nuclear force?

  It binds nucleons together at short distances
• What environment is necessary for fusion to occur?

  An extremely hot environment
• What is nuclear fission defined as?

  The splitting of a large atomic nucleus

  
• Which type of nuclei can undergo fission?

  High mass nuclei like uranium
• What must happen for fission to occur?

  Neutrons must be fired at a nucleus
• What happens when a nucleus is struck by a neutron during fission?

  It splits into two or more daughter nuclei

  
• What is ejected during fission?

  Neutrons
• What can ejected neutrons do during fission?

  Collide with other nuclei to trigger a cascade
• What is a chain reaction in nuclear fission?

  A series of fission events triggered by ejected neutrons

  
• What controls nuclear fission in power stations?

  It is well controlled
• What happens when nuclear fission is not controlled?

  It can produce the effects of a nuclear bomb
• What is the formula for calculating binding energy?

  E = (Δm)c
• What does Δm represent in the binding energy formula?

  Mass defect
• What is the relationship between daughter nuclei and parent nuclei in terms of binding energy?

  Daughter nuclei have higher binding energy per nucleon
• What is the binding energy per nucleon of U-235?

  7.59 MeV
• What is the binding energy per nucleon of Tc-112?

  8.36 MeV
• What is the binding energy per nucleon of In-122?

  8.51 MeV
• How do you calculate binding energy before fission for U-235?

  Binding energy = 235 × 7.59
• How do you calculate binding energy after fission for Tc-112 and In-122?

  Binding energy = (112 × 8.36) + (122 × 8.51)
• How do you find the energy released during fission?

  Energy released = 1975 – 1784
• How do you convert energy released from MeV to J?

  Energy released = 191 × (1.60 × 10$-13$)

  
• What is the equation for mass-energy equivalence?

  E = Δmc

  
• How do you determine the mass defect, Δm?

  Δm = E/c
• How do you convert energy released from MeV to atomic mass units (u)?

  Δm = 0.205 × (1.66 × 10$-27$)

  
• What are the steps to calculate energy released in nuclear fission?

  1. Determine binding energies before and after fission.
  2. Calculate the difference in binding energy.
  3. Convert energy from MeV to J if necessary.

  
• What are the methods to calculate mass defect?

  • Convert energy released from MeV to J.
  • Convert energy released from MeV to atomic mass units (u).

  
• What are the differences between nuclear fusion and fission?

  • Fusion: Combining small nuclei, releases energy.
  • Fission: Splitting large nuclei, releases energy.