AQA A level Physics ~ Nuclear physics
questions with verified answers
Explain what is meant be a chain reaction. - correct answers-When U-235 captures a thermal neutron,
undergoing fission and releasing more neutrons. These neutrons cause further fission reactions to occur.
What is the purpose of a moderator? - correct answers-To reduce the kinetic energy of neutrons so that
they can cause uranium fuel to undergo fission efficiently.
Why does the shielding of a nuclear reactor become radioactive? - correct answers-It absorbs neutrons
that collide with nuclei in the shielding, converting them into unstable isotopes.
What is meant by a thermal neutron? - correct answers-A slow moving neutron that is in thermal
equilibrium with the moderator. (Has energy = 0.025 eV and Kinetic energy similar to a gas at 300K)
How are actual moderator collisions different from models? - correct answers-- Collisions are rarely
head-on
- KE loss is variable
- Collisions are not always elastic
- Ratio if mass of a neutron to mass of a nucleus is much smaller
What is meant by the binding energy of a nucleus? - correct answers-The amount of energy required to
separate a nucleus into it's constituents
Describe the change that reduces a nuclear reactors power output - correct answers-Inserting the
control rods into the nuclear reactor core absorbs neutrons reducing the frequency of further fission
reactions.
Describe the nature of radiation emitted from an excited nucleus in the moderator - correct answers-
Electromagnetic radiation such as gamma rays as the energy released will be large due to the large gaps
in discrete energy levels to reach the ground state
What are 6 examples of background radiation? - correct answers-Cosmic rays, medical procedures,
radon gas, rocks, food and drink, Carbon-14
What is the typical range of alpha radiation in air? - correct answers-0.03m
What is the typical range of beta radiation in air? - correct answers-1m
Why does the count rate of gamma radiation reduce as the detector is moved further away? - correct
answers-The gamma radiation spreads out over a larger area and the intensity detected in inversely
proportional to the square of the displacement. (Inverse square law)
What is the most hazardous aspect of alpha radiation? - correct answers-- Highly ionising
Why is Technetium-99 a suitable source for medical diagnosis? - correct answers-- It has a low toxicity
rating
questions with verified answers
Explain what is meant be a chain reaction. - correct answers-When U-235 captures a thermal neutron,
undergoing fission and releasing more neutrons. These neutrons cause further fission reactions to occur.
What is the purpose of a moderator? - correct answers-To reduce the kinetic energy of neutrons so that
they can cause uranium fuel to undergo fission efficiently.
Why does the shielding of a nuclear reactor become radioactive? - correct answers-It absorbs neutrons
that collide with nuclei in the shielding, converting them into unstable isotopes.
What is meant by a thermal neutron? - correct answers-A slow moving neutron that is in thermal
equilibrium with the moderator. (Has energy = 0.025 eV and Kinetic energy similar to a gas at 300K)
How are actual moderator collisions different from models? - correct answers-- Collisions are rarely
head-on
- KE loss is variable
- Collisions are not always elastic
- Ratio if mass of a neutron to mass of a nucleus is much smaller
What is meant by the binding energy of a nucleus? - correct answers-The amount of energy required to
separate a nucleus into it's constituents
Describe the change that reduces a nuclear reactors power output - correct answers-Inserting the
control rods into the nuclear reactor core absorbs neutrons reducing the frequency of further fission
reactions.
Describe the nature of radiation emitted from an excited nucleus in the moderator - correct answers-
Electromagnetic radiation such as gamma rays as the energy released will be large due to the large gaps
in discrete energy levels to reach the ground state
What are 6 examples of background radiation? - correct answers-Cosmic rays, medical procedures,
radon gas, rocks, food and drink, Carbon-14
What is the typical range of alpha radiation in air? - correct answers-0.03m
What is the typical range of beta radiation in air? - correct answers-1m
Why does the count rate of gamma radiation reduce as the detector is moved further away? - correct
answers-The gamma radiation spreads out over a larger area and the intensity detected in inversely
proportional to the square of the displacement. (Inverse square law)
What is the most hazardous aspect of alpha radiation? - correct answers-- Highly ionising
Why is Technetium-99 a suitable source for medical diagnosis? - correct answers-- It has a low toxicity
rating
