Nuclear

Question 1

What is meant by the term binding energy

Answer 1

The work that must be done to separate a nucleus into its constituent neutrons and protons

Question 2

Define the atomic mass unit, u

Answer 2

one twelfth of the mass of a carbon 12 atom

Question 3

Why must nuclei in stars be at high temperatures for fusion to take place.

Answer 3

• Nuclei need to be close together such that the strong nuclear force takes action
• To to this they must overcome the electrostatic force
• Therefore they need a high kinetic energy which can be provided by high temperatures

Question 4

Describe and explain the nature of radiation released by an excited nucleus de-exciting

Answer 4

Gamma radiation is released since the energy level of an excited nucleus are far apart and using E = hf we see that a larger energy gap must give a large frequency e.g. gamma

Question 5

Compare the kinetic energies of emitted alpha particles vs beta particles and explain your answer.

Answer 5

• Energy released from decay is based upon mass defect
• Alpha particles have a constant mass and are the only particle released in an alpha decay and hence always have the same kinetic energy
• The kinetic energies of beta particles vary up to a maximum
• The maximum is the total energy released in the decay, again based on the mass defect
• However this energy is distributed across the beta particle and antineutrino
• Therefore the kinetic energies of beta particles released vary from decay to decay