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6.0 Atomic and
Nuclear Physics, 12.0 Quantum Physics and
Nuclear Physics
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Section Number
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Topic
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Descriptor
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Topic 6: Atomic
and Nuclear Physics (9h)
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6.1 The Atom
(2h)
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Atomic
structure
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6.1.1
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Describe a model of the atom
that features a small nucleus surrounded by
electrons.
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6.1.2
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Outline the evidence that
supports a nuclear model of the atom.
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A qualitative
explanation of the Geiger-Marsden experiment and its
results is all that is
required.
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6.1.3
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Outline evidence for the
existence of atomic energy levels.
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Students should be
familiar with emission and absorption spectra, but
the details of
atomic models are not required.
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Nuclear
structure
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6.1.4
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Describe the existence of
isotopes as evidence for neutrons.
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6.1.5
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Explain the terms nuclide,
isotope and nucleon.
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6.1.6
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Define mass number and
atomic number.
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6.1.7
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Describe the interactions in
the nucleus.
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Students should be
aware that there is a Coulomb interaction between
protons and a strong,
short-range nuclear interaction between the
nucleons.
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6.2 Radioactive
Decay (3h)
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Radioactivity
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6.2.1
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Describe the phenomenon of
natural radioactive decay.
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6.2.2
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Describe alpha, beta and gamma
radiation and their properties.
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6.2.3
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Describe the ionizing
properties of radiation and its use in the detection
of radiation.
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The Geiger-Muller
tube and the ionization chamber are examples of such
detection devices. Only
a qualitative understanding of the operation of
these devices is
required.
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6.2.4
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Explain why some nuclei are
stable while others are unstable.
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An explanation in
terms of relative numbers of protons and neutrons and
the forces involved is
all that is required.
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6.2.5
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Determine the atomic and mass
numbers of the products of nuclear decay in
a transformation or in a series
of transformations.
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Positron decay and
the inclusion of the antineutrino in beta minus decay
are not required but
teachers should not artificially avoid mentioning
them.
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Half-life
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6.2.6
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State that radioactive decay
is a random process and that the average rate of
decay for a sample of a
radioactive isotope decreases exponentially with
time.
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Exponential decay
need not be treated analytically. It is sufficient to
know that any
quantity that reduces to half its initial value in a
constant time decays
exponentially and that this law does not depend on the
initial amount
of the quantity.
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6.2.7
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Define the term
half-life.
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6.2.8
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Determine the half-life of a
nuclide from a decay curve.
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It is sufficient for
students to find a halving-time.
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6.2.9
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Solve radioactive decay
problems involving integral numbers of
half-lives.
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6.3 Nuclear
Reactions, Fission and Fusion (4h)
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Nuclear
reactions
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6.3.1
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Describe and give an example
of artificial (induced) transmutation.
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6.3.2
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Construct and complete nuclear
reaction equations.
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For example,
H O N He
1117814742
+ =
+6 1 3 43 0 1 2
+ = + Li n H
He
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6.3.3
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Define the term unified
mass unit.
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6.3.4
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State and apply Einstein's
mass-energy equivalence relationship.
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6.3.5
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Explain the concepts of mass
defect and binding energy.
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6.3.6
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Solve problems involving mass
defect and binding energies.
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Fission and
fusion
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6.3.7
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Describe the processes of
nuclear fission and fusion.
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Students should be
familiar with the concept of a chain reaction.
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6.3.8
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Draw and annotate a graph of
binding energy per nucleon against atomic
number Z, and apply it to predict
nuclear energy changes for both the fission
and fusion processes.
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6.3.9
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State that nuclear fusion is
the main source of the Sun's energy.
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6.3.10
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Solve problems involving
fission and fusion reactions.
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Topic 12:
Quantum Physics and Nuclear Physics
(15h)
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12.1 Quantum
Physics (9h)
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The quantum
nature of radiation
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12.1.1
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Describe the photoelectric
effect and Einstein's explanation of this effect.
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Students should be
familiar with the concept of the photon and should be
able to explain why the
wave model of light is unable to explain the
photoelectric
effect.
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12.1.2
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Outline an experiment to test
the Einstein model.
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Millikan's
experiment involving the application of a stopping
potential would
be a suitable example.
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12.1.3
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Solve problems involving the
photoelectric effect.
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The wave nature
of matter
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12.1.4
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Describe de Broglie's
hypothesis and the concept of matter waves.
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Students should also
be aware of wave-particle duality (the dual nature of
both radiation and
matter).
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12.1.5
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Outline an experiment to test
the de Broglie hypothesis.
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12.1.6
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Solve problems involving
matter waves.
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For example,
students should be able to calculate the wavelength of
moving electrons.
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Atomic spectra
and atomic energy states
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12.1.7
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Outline how atomic spectra can
be observed.
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12.1.8
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Explain how atomic spectra
provide evidence for the quantization of energy
in atoms.
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An explanation in
terms of energy differences between allowed electron
energy states is
sufficient.
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12.1.9
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Outline the Bohr model of the
hydrogen atom.
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No mathematical
details are required. Refer to the fact that the
model enabled
the discrete wavelengths of the hydrogen spectrum to be
predicted.
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12.1.10
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State the limitations of the
Bohr model.
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12.1.11
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Outline the Schršdinger
model of the hydrogen atom.
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The model assumes
that electrons in the atom can be described by wave
functions. These have
to fit boundary conditions in three dimensions in the
atom, giving rise to
both radial and angular allowed modes with discrete
energy states
(analogous to the discrete allowed frequencies of
standing waves).
The electron has an undefined position, but the square of
the amplitude of
the wave function gives the probability of finding it at
a point.
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12.1.12
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Calculate spectral wavelengths
from energy level differences and vice versa.
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X-rays
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12.1.13
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Outline the experimental set
up for the production of X-rays.
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12.1.14
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Draw and annotate a typical
X-ray spectrum.
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Students should be
able to identify the continuous and characteristic
features of the
spectrum and the minimum wavelength limit.
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12.1.15
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Explain the origins of the
features of a typical X-ray spectrum.
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12.2 Nuclear
Physics (3h)
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The
nucleus
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12.2.1
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Explain how the radii of
nuclei can be determined by charged particle
scattering
experiments.
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Use of energy
conservation for determining closest-approach distances
for Coulomb
scattering experiments is sufficient.
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12.2.2
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Describe how the masses of
nuclei can be determined using a mass spectrometer.
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Students should be
able to draw a schematic diagram of the mass
spectrometer but the
experimental details are not required. Students
should appreciate
that nuclear mass values provided evidence for the existence
of isotopes.
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12.2.3
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Describe one piece of evidence
for the existence of nuclear energy levels.
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For example, alpha
particles produced by the decay of a nuclide have
discrete energies;
gamma ray spectra are discrete. Students should
appreciate that the
nucleus, like the atom, is a quantum system with
allowed states and
discrete energy levels.
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Radioactive
decay
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12.2.4
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Describe
both
£]+ and £]- decay,
including the existence of the neutrino and
the antineutrino.
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Students should know
that £]
energy spectra
are continuous and that the neutrino
was postulated to account for the missing energy and
momentum.
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12.2.5
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State the radioactive decay
law as an exponential function and define the
decay constant.
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12.2.6
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Derive the relationship
between the decay constant and half-life.
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12.2.7
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Solve problems using the
radioactive decay law.
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12.2.8
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Outline methods for measuring
the half-life of an isotope.
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Students should know
the principles of measurement for both long and
short
half-lives.
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12.3 Particle
Physics (3h)
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Note: This section is
intended to be a brief factual introduction to
particle physics.
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12.3.1
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Outline the concept of
antiparticles and give examples.
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12.3.2
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Outline the concepts of
particle production and annihilation and apply the
conservation laws to these
processes.
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Students should know
that particles can be produced in high-energy
interactions in
particle accelerators. Details of accelerators are
not required.
Students should appreciate that these processes are
instances of the conversion
of energy to rest mass and vice versa (in accordance
with Einstein's
mass-energy relation), and are subject to various
conservation laws:
mass-energy, momentum, electric charge, lepton number and
baryon number.
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12.3.3
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List and outline the four
fundamental interactions.
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Students should also
be aware that the electromagnetic force and weak
nuclear force are
instances of a single electroweak force with two types
of exchange
particles.
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12.3.4
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List the three classes of
fundamental particle.
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It is sufficient to
know that the classes are leptons, quarks and
exchange bosons
(force mediators), and that there are six types of quarks
and leptons,
plus their antiparticles, grouped in three generations.
Students should
know that isolated quarks have not been detected.
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12.3.5
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State that there are three
classes of observed particle.
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It is sufficient to
know that the classes are leptons, hadrons and
exchange bosons.
Hadrons are divided into mesons and baryons.
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12.3.6
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Outline the structure of
nucleons in terms of quarks.
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Students should be
able to relate nucleon properties to composition, eg
describe protons as
Òup, up, downÓ.
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12.3.7
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Outline the concept of an
interaction as mediated by exchange of particles.
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Students should be
able to associate the four interactions with their
respective exchange
particles and should also be aware of the colour
force between
quarks and the associated gluons.
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