### Rationale/Aims

Physics is a fundamental science that endeavours to explain all the natural phenomena that occur in the universe. Its power lies in the use of a comparatively small number of assumptions, models, laws and theories to explain a wide range of phenomena, from the incredibly small to the incredibly large.### Structure of Physics

In Physics, students develop their understanding of the core concepts, models and theories that describe, explain and predict physical phenomena.### Links to Foundation to Year 10

The Physics curriculum continues to develop student understanding and skills from across the three strands of the F-10 Australian Curriculum: Science. In the Science Understanding strand, the Physics curriculum draws on knowledge and understanding from across the four sub-strands of Biological, Physical, Chemical and Earth and Space Sciences.### Representation of Cross-curriculum priorities

While the significance of the cross-curriculum priorities for Physics varies, there are opportunities for teachers to select contexts that incorporate the key concepts from each priority.### Achievement standards

## Unit 1: Thermal, nuclear and electrical physics

### Unit 1: Thermal, nuclear and electrical physics Description

An understanding of heating processes, nuclear reactions and electricity is essential to appreciate how global energy needs are met. In this unit, students explore the ways physics is used to describe, explain and predict the energy transfers and transformations that are pivotal to modern industrial societies. Students investigate heating processes, apply the nuclear model of the atom to investigate radioactivity, and learn how nuclear reactions convert mass into energy. They examine the movement of electrical charge in circuits and use this to analyse, explain and predict electrical phenomena.

Contexts that could be investigated in this unit include technologies related to nuclear, thermal, or geothermal energy, electrical energy production, large-scale power systems, radiopharmaceuticals and electricity in the home; and related areas of science such as nuclear fusion in stars and the Big Bang theory.

Through the investigation of appropriate contexts, students understand how applying scientific knowledge to the challenge of meeting world energy needs requires the international cooperation of multidisciplinary teams and relies on advances in ICT and other technologies. They explore how science knowledge is used to offer valid explanations and reliable predictions, and the ways in which it interacts with social, economic, cultural and ethical factors.

Students develop skills in interpreting, constructing and using a range of mathematical and symbolic representations to describe, explain and predict energy transfers and transformations in heating processes, nuclear reactions and electrical circuits. They develop their inquiry skills through primary and secondary investigations, including analysing heat transfer, heat capacity, radioactive decay and a range of simple electrical circuits.

### Unit 1: Thermal, nuclear and electrical physics Learning Outcomes

By the end of this unit, students:

- understand how the kinetic particle model and thermodynamics concepts describe and explain heating processes
- understand how the nuclear model of the atom explains radioactivity, fission, fusion and the properties of radioactive nuclides
- understand how charge is involved in the transfer and transformation of energy in electrical circuits
- understand how scientific models and theories have developed and are applied to improve existing, and develop new, technologies
- use science inquiry skills to design, conduct and analyse safe and effective investigations into heating processes, nuclear physics and electrical circuits, and to communicate methods and findings
- use algebraic and graphical representations to calculate, analyse and predict measurable quantities associated with heating processes, nuclear reactions and electrical circuits
- evaluate, with reference to empirical evidence, claims about heating processes, nuclear reactions and electrical technologies
- communicate physics understanding using qualitative and quantitative representations in appropriate modes and genres.

### Unit 1: Thermal, nuclear and electrical physics Content Descriptions

#### Science Inquiry Skills

Identify, research, construct and refine questions for investigation; propose hypotheses; and predict possible outcomes (ACSPH001)

Design investigations, including the procedure/s to be followed, the materials required, and the type and amount of primary and/or secondary data to be collected; conduct risk assessments; and consider research ethics (ACSPH002)

Conduct investigations, including using temperature, current and potential difference measuring devices, safely, competently and methodically for the collection of valid and reliable data (ACSPH003)

Represent data in meaningful and useful ways, including using appropriate Système Internationale (SI) units and symbols; organise and analyse data to identify trends, patterns and relationships; identify sources of random and systematic error and estimate their effect on measurement results; identify anomalous data and calculate the measurement discrepancy between experimental results and a currently accepted value, expressed as a percentage; and select, synthesise and use evidence to make and justify conclusions (ACSPH004)

Interpret a range of scientific and media texts, and evaluate processes, claims and conclusions by considering the quality of available evidence; and use reasoning to construct scientific arguments (ACSPH005)

Select, construct and use appropriate representations, including text and graphic representations of empirical and theoretical relationships, flow diagrams, nuclear equations and circuit diagrams, to communicate conceptual understanding, solve problems and make predictions (ACSPH006)

Select, use and interpret appropriate mathematical representations, including linear and non-linear graphs and algebraic relationships representing physical systems, to solve problems and make predictions (ACSPH007)

Communicate to specific audiences and for specific purposes using appropriate language, nomenclature, genres and modes, including scientific reports (ACSPH008)

#### Science as a Human Endeavour (Units 1 & 2)

Science is a global enterprise that relies on clear communication, international conventions, peer review and reproducibility (ACSPH009)

Development of complex models and/or theories often requires a wide range of evidence from multiple individuals and across disciplines (ACSPH010)

Advances in science understanding in one field can influence other areas of science, technology and engineering (ACSPH011)

The use of scientific knowledge is influenced by social, economic, cultural and ethical considerations (ACSPH012)

The use of scientific knowledge may have beneficial and/or harmful and/or unintended consequences (ACSPH013)

Scientific knowledge can enable scientists to offer valid explanations and make reliable predictions (ACSPH014)

Scientific knowledge can be used to develop and evaluate projected economic, social and environmental impacts and to design action for sustainability (ACSPH015)

#### Science Understanding

#### Heating processes

**Examples in context**

Support materials only that illustrate some possible contexts for exploring Science as a Human Endeavour concepts in relation to Science Understanding content.

## Energy security and sustainability - emerging energy sources

The science of heating processes is of key importance to predicting future energy needs and the best mix of energy sources to meet these needs (ACSPH015). Sustainable energy production will require renewable energy sources that can be used alongside current power generation methods. Development of efficient and cost-effective methods for harnessing renewable energy sources such as solar and geothermal energy is dependent upon understanding of heating processes and energy transfers and transformations (ACSPH015). It has been difficult to predict future energy usage accurately. The complexity of the problem is compounded by factors including the emergence of new energy sources, improvements in the efficiency of existing energy sources, improved scientific understanding, changes in demand and social, economic and political pressures (ACSPH012).

## Energy balance of Earth

Circulation of energy in the atmosphere and oceans evens out solar heating imbalances on the planet’s surface, resulting in a more uniform temperature distribution. Increases in incoming or outgoing energy disturb Earth’s radiative equilibrium and affect global temperatures. Predictions of human-induced climate change and the possible effects of such change rely heavily on the science of heating processes (ACSPH014). Predictions are refined and improved as new data becomes available and scientific understanding improves, but the complexity and number of the assumptions involved prevents scientists from providing absolutely definite answers (ACSPH014). New technologies are being developed to address both the cause of human-induced climate change and the consequent effects on the natural and built environment (ACSPH011).

## Development of thermodynamics

The development of thermodynamic theory arose from a need to increase the efficiency of early steam engines, and led to important technological developments including the internal combustion engine, cryogenics and electricity generation. The development of the steam engine through the Savery and Watt engines led to important advances in the understanding of heat processes, energy transfer and transformation, and how heating can be used to do mechanical work (ACSPH010). Pioneers in this field, such as Joseph Black, Lavoisier and James Joule, produced quantitative, reproducible experiments that increased understanding of thermodynamics (ACSPH009). Other scientists, including Rankine, Kelvin, Maxwell and Gibbs, built further on this work, leading to the development of important laws and theories such as the gas laws, the laws of thermodynamics, and concepts such as heat capacity and latent heat (ACSPH010).

**Mathematical representations and relationships**

\(\mathrm Q=\mathrm m\mathrm c\operatorname\Delta\mathrm T\)

\(\mathrm Q=\;\) heat transferred to or from the object,

\(\mathrm m=\;\) mass of object, \mathrm c=\; specific heat capacity of the object,

\(\;\operatorname\Delta\mathrm T=\;\) temperature change

\(\mathrm Q=\mathrm m\mathrm L\)

\(\mathrm Q=\;\)heat transferred to or from the object,

\(\mathrm L=\;\) latent heat capacity of the material,

\(\mathrm m=\;\) mass of object

\(\mathrm\eta\;=\;\frac{\mathrm e\mathrm n\mathrm e\mathrm r\mathrm g\mathrm y\;\mathrm o\mathrm u\mathrm t\mathrm p\mathrm u\mathrm t}{\mathrm e\mathrm n\mathrm e\mathrm r\mathrm g\mathrm y\;\mathrm i\mathrm n\mathrm p\mathrm u\mathrm t}\;\;\times\;\frac{100}1\%\)

\(\mathrm\eta=\;\) efficiency

Heat transfer occurs between and within systems by conduction, convection and/or radiation (ACSPH016)

The kinetic particle model describes matter as consisting of particles in constant motion, except at absolute zero (ACSPH017)

All systems have thermal energy due to the motion of particles in the system (ACSPH018)

Temperature is a measure of the average kinetic energy of particles in a system (ACSPH019)

Provided a substance does not change state, its temperature change is proportional to the amount of energy added to or removed from the substance; the constant of proportionality describes the heat capacity of the substance (ACSPH020)

Change of state involves internal energy changes to form or break bonds between atoms or molecules; latent heat is the energy required to be added to or removed from a system to change the state of the system (ACSPH021)

Two systems in contact transfer energy between particles so that eventually the systems reach the same temperature; that is, they are in thermal equilibrium (ACSPH022)

A system with thermal energy has the capacity to do mechanical work (that is, to apply a force over a distance); when work is done, the internal energy of the system changes (ACSPH023)

Because energy is conserved, the change in internal energy of a system is equal to the energy added or removed by heating plus the work done on or by the system (ACSPH024)

Energy transfers and transformations in mechanical systems (for example, internal and external combustion engines, electric motors) always result in some heat loss to the environment, so that the usable energy is reduced and the system cannot be 100 percent efficient (ACSPH025)

#### Ionising radiation and nuclear reactions

**Examples in context**

Support materials only that illustrate some possible contexts for exploring Science as a Human Endeavour concepts in relation to Science Understanding content.

## Radioisotopes and radiometric dating

Radiometric dating of materials utilises a variety of methods depending on the age of the substances to be dated. The presence of natural radioisotopes in materials such as carbon, uranium, potassium and argon and knowledge about their half life and decay processes enables scientists to develop accurate geologic timescales and geologic history for particular regions (ACSPH011). This information is used to inform study of events such as earthquakes and volcanic eruptions, and helps scientists to predict their behaviour based on past events (ACSPH014). Dating of wood and carbon-based materials has also led to improvements in our understanding of more recent history through dating of preserved objects (ACSPH014).

## Harnessing nuclear power

Knowledge of the process of nuclear fission has led to the ability to use nuclear power as a possible long-term alternative to fossil fuel electricity generation (ACSPH013). Nuclear power has been used very successfully to produce energy in many countries but has also caused significant harmful consequences in a number of specific instances (ACSPH013). Analysis of health and environmental risks and weighing these against environmental and cost benefits is a scientific and political issue in Australia which has economic, cultural and ethical aspects (ACSPH012). The management of nuclear waste is based on knowledge of the behaviour of radiation. Current proposals for waste storage in Australia attempt to address the unintended harmful consequences of the use of radioactive substances (ACSPH013).

## Nuclear fusion in stars

Energy production in stars was attributed to gravity until knowledge of nuclear reactions enabled understanding of nuclear fusion. Almost all the energy used on Earth has its origin in the conversion of mass to energy that occurs when hydrogen nuclei fuse together to form helium in the core of the sun (ACSPH010). According to the Big Bang Theory, all the elements heavier than helium have been created by fusion in stars. The study of nuclear fusion in the sun has produced insights into the formation and life cycle of stars (ACSPH010). An unexpected consequence of early understanding of fusion in stars was its use to inform the development of thermonuclear weapons (ACSPH010). Research is ongoing into the use of fusion as an alternative power source (ACSPH013).

**Mathematical representations and relationships**

\(\mathrm N={\mathrm N}_\mathrm o\left(\frac12\right)^\mathrm n\) (for whole numbers of half-lives only)

\(\mathrm N=\;\) number of nuclides remaining in a sample, \(\mathrm n\;\)= number of whole half-lives,

\(\operatorname\Delta\mathrm E\;=\operatorname\Delta\mathrm m\mathrm c^2\;\)

\({\mathrm N}_\mathrm o=\;\) original number of nuclides in the sample

\(\triangle\mathrm E=\;\) energy change, \(\operatorname\Delta\mathrm m=\;\) mass change, \(\mathrm c=\;\) speed of light

\(\left(3\;\times10^8\;\text{m }\text{s}^{-1}\right)\)

The nuclear model of the atom describes the atom as consisting of an extremely small nucleus, which contains most of the atom’s mass and is made up of positively charged protons and uncharged neutrons surrounded by negatively charged electrons (ACSPH026)

Nuclear stability is the result of the strong nuclear force, which operates between nucleons over a very short distance and opposes the electrostatic repulsion between protons in the nucleus (ACSPH027)

Some nuclides are unstable and spontaneously decay, emitting alpha, beta and/or gamma radiation over time until they become stable nuclides (ACSPH028)

Each species of radionuclide has a specific half-life (ACSPH029)

Alpha, beta and gamma radiation have sufficient energy to ionise atoms (ACSPH030)

Einstein’s mass/energy relationship, which applies to all energy changes, enables the energy released in nuclear reactions to be determined from the mass change in the reaction (ACSPH031)

Alpha and beta decay are examples of spontaneous transmutation reactions, while artificial transmutation is a managed process that changes one nuclide into another (ACSPH032)

Neutron-induced nuclear fission is a reaction in which a heavy nuclide captures a neutron and then splits into two smaller radioactive nuclides, with the release of neutrons and energy (ACSPH033)

A fission chain reaction is a self-sustaining process that may be controlled to produce thermal energy, or uncontrolled to release energy explosively (ACSPH034)

Nuclear fusion is a reaction in which light nuclides combine to form a heavier nuclide, with the release of energy (ACSPH035)

More energy is released per nucleon in nuclear fusion than in nuclear fission because a greater percentage of the mass is transformed into energy (ACSPH036)

#### Electrical circuits

**Examples in context**

Support materials only that illustrate some possible contexts for exploring Science as a Human Endeavour concepts in relation to Science Understanding content.

## Electrical energy in the home

The supply of electricity to homes has had an enormous impact on society and the environment. An understanding of Kirchhoff’s circuit laws informs the design of circuits for effective and safe operation of lighting, power points, stoves and other household electrical devices (ACSPH015). Increases in the use of household electricity due to extreme weather in Australian summers and European winters creates problems in supply, causing brownouts, power failures and damage to household appliances (ACSPH015). Developing new household electrical devices, improving the efficiency of existing devices and ensuring consistency of electrical standards require international cooperation between scientists, engineers and manufacturers (ACSPH009).

## Powering the digital age

Computers, smartphones and the internet have changed the world, but none would be possible without a reliable supply of electricity. The first batteries, which enabled the investigation of current electricity, were developed by Alessandro Volta after a chance discovery by Luigi Galvani about the production of electricity (ACSPH010). Later, Michael Faraday developed the first electric generators and the ‘electrical age’ began. With the development of smartphones, tablets and similar devices that allow for constant communication and information flow, the design of long-lasting batteries to power these devices is an industry priority (ACSPH014). Long-lasting battery technology is also essential for safety devices like GPS locators, satellite phones and emergency beacons.

## Electric lighting

The introduction of electric lighting had a significant impact on society and the environment. The first efficient electric lamps were the filament lamps developed by Thomas Edison in the 1880s. Since that time, social, economic and cultural influences have led to development of a vast array of electric light sources including fluorescent lamps, halogen lamps, sodium lamps, light-emitting diodes and lasers (ACSPH012). Research and development of electric light sources has been underpinned by developments in our understanding of electricity, atomic physics and electromagnetism. Concerns about sustainable energy usage and global warming have led to international research and development to improve the energy efficiency of electric lighting (ACSPH015).

**Mathematical representations and relationships**

\(\mathrm I=\;\frac{\mathrm q}{\mathrm t}\)

\(\mathrm V=\frac{\mathrm W}{\mathrm q}\)

\(\mathrm R=\frac{\mathrm V}{\mathrm I}\)

\(\mathrm P=\frac{\mathrm W}{\mathrm t}=\mathrm V\mathrm I\)

Equivalent resistance for series components, \(\mathrm I=\;\) constant

\({\mathrm V}_\mathrm t={\mathrm V}_1+{\mathrm V}_2+..{\mathrm V}_\mathrm n\)

\({\mathrm R}_\mathrm t={\mathrm R}_1+{\mathrm R}_2+..{\mathrm R}_\mathrm n\)

Equivalent resistance for parallel components, \(\mathrm V=\) constant

\({\mathrm I}_\mathrm t={\mathrm I}_1+{\mathrm I}_2+..{\mathrm I}_\mathrm n\;\)

\(\frac1{{\mathrm R}_\mathrm t}=\frac1{{\mathrm R}_1}+\frac1{{\mathrm R}_2}+..\frac1{{\mathrm R}_\mathrm n}\)

\(\mathrm I=\;\) current, V_subscript_t= total potential difference, \({\mathrm V}_\mathrm n\) = the potential difference across each component, \({\mathrm R}_\mathrm t=\;\) equivalent resistance, \({\mathrm R}_\mathrm n\) = resistance of each component

\({\mathrm I}_\mathrm t={\mathrm I}_1+{\mathrm I}_2+..{\mathrm I}_\mathrm n\;\)

\(\mathrm V=\) potential difference, \({\mathrm I}_\mathrm t=\;\)= total current, \({\mathrm I}_\mathrm n\) = current in each of the components, \(\frac1{{\mathrm R}_\mathrm t}=\;\) the reciprocal of the equivalent resistance, \(\;\frac1{{\mathrm R}_\mathrm n}=\;\)= the reciprocal of the resistance of each component

Electrical circuits enable electrical energy to be transferred efficiently over large distances and transformed into a range of other useful forms of energy including thermal and kinetic energy, and light. (ACSPH037)

Electric current is carried by discrete charge carriers; charge is conserved at all points in an electrical circuit (ACSPH038)

Energy is conserved in the energy transfers and transformations that occur in an electrical circuit (ACSPH039)

The energy available to charges moving in an electrical circuit is measured using electric potential difference, which is defined as the change in potential energy per unit charge between two defined points in the circuit (ACSPH040)

Energy is required to separate positive and negative charge carriers; charge separation produces an electrical potential difference that can be used to drive current in circuits (ACSPH041)

Power is the rate at which energy is transformed by a circuit component; power enables quantitative analysis of energy transformations in the circuit (ACSPH042)

Resistance for ohmic and non-ohmic components is defined as the ratio of potential difference across the component to the current in the component (ACSPH043)

Circuit analysis and design involve calculation of the potential difference across, the current in, and the power supplied to, components in series, parallel and series/parallel circuits (ACSPH044)

## Unit 2: Linear Motion and Waves

### Unit 2: Linear Motion and Waves Description

In this unit, students develop an appreciation of how an understanding of motion and waves can be used to describe, explain and predict a wide range of phenomena. Students describe linear motion in terms of position and time data, and examine the relationships between force, momentum and energy for interactions in one dimension.

Students investigate common wave phenomena, including waves on springs, and water, sound and earthquake waves, and compare the behaviour of these waves with the behaviour of light. This leads to an explanation of light phenomena, including polarisation, interference and diffraction, in terms of a wave model.

Contexts that could be investigated in this unit include technologies such as accelerometers, motion-detectors, photo radar, GPS, energy conversion buoys, music, hearing aids, echo locators, fibre optics, DVDs and lasers, and related areas of science and engineering such as sports science, car and road safety, acoustic design, noise pollution, seismology, bridge and building design.

Through the investigation of appropriate contexts, students explore how international collaboration, evidence from a range of disciplines and many individuals, and the development of ICT and other technologies have contributed to developing understanding of motion and waves and associated technologies. They investigate how scientific knowledge is used to offer valid explanations and reliable predictions, and the ways in which it interacts with social, economic, cultural and ethical factors.

Students develop their understanding of motion and wave phenomena through laboratory investigations. They develop skills in relating graphical representations of data to quantitative relationships between variables, and they continue to develop skills in planning, conducting and interpreting the results of primary and secondary investigations.

### Unit 2: Linear Motion and Waves Learning Outcomes

By the end of this unit, students:

- understand that Newton’s Laws of Motion describe the relationship between the forces acting on an object and its motion
- understand that waves transfer energy and that a wave model can be used to explain the behaviour of sound and light
- understand how scientific models and theories have developed and are applied to improve existing, and develop new, technologies
- use science inquiry skills to design, conduct and analyse safe and effective investigations into linear motion and wave phenomena, and to communicate methods and findings
- use algebraic and graphical representations to calculate, analyse and predict measurable quantities associated with linear and wave motion
- evaluate, with reference to evidence, claims about motion, sound and light-related phenomena and associated technologies
- communicate physics understanding using qualitative and quantitative representations in appropriate modes and genres.

### Unit 2: Linear Motion and Waves Content Descriptions

#### Science Inquiry Skills

Identify, research and construct questions for investigation; propose hypotheses; and predict possible outcomes (ACSPH045)

Design investigations, including the procedure to be followed, the materials required, and the type and amount of primary and/or secondary data to be collected; conduct risk assessments; and consider research ethics (ACSPH046)

Conduct investigations, including the manipulation of devices to measure motion and the direction of light rays, safely, competently and methodically for the collection of valid and reliable data (ACSPH047)

Represent data in meaningful and useful ways, including using appropriate SI units and symbols; organise and analyse data to identify trends, patterns and relationships; identify sources of random and systematic error and estimate their effect on measurement results; identify anomalous data and calculate the measurement discrepancy between the experimental results and a currently accepted value, expressed as a percentage; and select, synthesise and use evidence to make and justify conclusions (ACSPH048)

Interpret a range of scientific and media texts, and evaluate processes, claims and conclusions by considering the quality of available evidence; and use reasoning to construct scientific arguments (ACSPH049)

Select, construct and use appropriate representations, including text and graphic representations of empirical and theoretical relationships, vector diagrams, free body/force diagrams, wave diagrams and ray diagrams, to communicate conceptual understanding, solve problems and make predictions (ACSPH050)

Select, use and interpret appropriate mathematical representations, including linear and non-linear graphs and algebraic relationships representing physical systems, to solve problems and make predictions (ACSPH051)

Communicate to specific audiences and for specific purposes using appropriate language, nomenclature, genres and modes, including scientific reports (ACSPH052)

#### Science as a Human Endeavour (Units 1 & 2)

Science is a global enterprise that relies on clear communication, international conventions, peer review and reproducibility (ACSPH053)

Development of complex models and/or theories often requires a wide range of evidence from multiple individuals and across disciplines (ACSPH054)

Advances in science understanding in one field can influence other areas of science, technology and engineering (ACSPH055)

The use of scientific knowledge is influenced by social, economic, cultural and ethical considerations (ACSPH056)

The use of scientific knowledge may have beneficial and/or harmful and/or unintended consequences (ACSPH057)

Scientific knowledge can enable scientists to offer valid explanations and make reliable predictions (ACSPH058)

Scientific knowledge can be used to develop and evaluate projected economic, social and environmental impacts and to design action for sustainability (ACSPH059)

#### Science Understanding

#### Linear motion and force

**Examples in context**

## Road safety and technology

Knowledge of forces and motion has led to developments that have reduced the risks for drivers, their passengers, and other road users such as cyclists and pedestrians. Car safety has improved through the development and use of devices such as seatbelts, crumple zones and airbags. An understanding of motion has also led to the design and implementation of traffic-calming devices such as speed bumps and safety barriers (ACSPH056). Knowledge of force and linear motion is used in forensic investigations into car accidents. Road laws and regulations, including the setting of speed limits in particular locations, are based on these scientific investigations and have resulted in lower road accident injuries and fatalities (ACSPH057).

## Sports science

The study of linear motion and forces has led to major developments in athlete training programs, sporting techniques and equipment development. Biomechanics applies the laws of force and motion to gain greater understanding of athletic performance through direct measurement, computer simulations and mathematical modelling (ACSPH054). Equipment such as bicycle frames and running shoes has been improved to reduce stresses and strains on athletes’ bodies. Many sports teams employ biomechanics experts to improve kicking, throwing or other techniques using knowledge of forces and motion. Advances in interpretation of video technologies, data logging and electronic detection and timing systems has also significantly improved reliability of judgements in sporting events (ACSPH055).

## Development and limitations of Newton’s Laws

Isaac Newton’s interest in how objects fall and the orbits of planets led to the writing and publication of Principia Mathematica, which outlined the Laws of Motion. Newton’s laws provided an explanation for a range of previously unexplained physical phenomena and were confirmed by multiple experiments performed by a multitude of scientists (ACSPH053). Newton’s laws of motion enable scientists to make reliable predictions, except when considering objects travelling at or near the speed of light, or very small objects like atoms or subatomic particles, or when very strong gravitational fields are involved (ACSPH058). Phenomena related to semiconductors, superconductors and errors in GPS systems cannot be predicted using Newton’s Laws and other theories must be used (ACSPH058).

**Mathematical representations and relationships**

\(\mathrm v=\mathrm u+\mathrm a\mathrm t,\; \) \(\mathrm s=\mathrm u\mathrm t+\frac12\mathrm a\mathrm t^2,\) \(\mathrm v^2=\mathrm u^2+2\mathrm a\mathrm s\)

\(\mathrm s=\;\) displacement, \(\mathrm t\) = time interval, \(\mathrm u=\) initial velocity, \(\mathrm v=\;\) final velocity, \(\mathrm a=\;\) acceleration

\(\mathrm a=\frac{\mathrm F}{\mathrm m}\)

\(\mathrm a=\;\) a= acceleration, \(\mathrm F=\) force, \(\mathrm m\;=\) mass

\(\mathrm W=\operatorname\Delta\mathrm E;\;\) where the applied force is in the same direction as the displacement, \(\mathrm W=\mathrm F\mathrm s,\;\)

\(\mathrm W\) = work, \(\;\mathrm F=\;\) force, \(\;\mathrm s=\) displacement, \(\operatorname\Delta\mathrm E=\;\) change in energy

\(\mathrm p=\mathrm m\mathrm v,\;\;\mathrm\Delta\mathrm p=\mathrm F\mathrm\Delta\mathrm t\)

\(\mathrm p\) = momentum, \(\mathrm v=\;\) velocity, \(\mathrm m\;=\) mass, \(\mathrm F\;\) = force, \(\triangle\mathrm p=\) change in momentum, \(\mathrm\Delta\mathrm t\) = time interval over which force \(\mathrm F\) acts

\({\mathrm E}_\mathrm k=\;\frac12\;\mathrm m\mathrm v^2\)

\({\mathrm E}_\mathrm k=\) kinetic energy, \(\;\mathrm m=\) mass, \(\mathrm v=\;\) speed

\(\operatorname\Delta{\mathrm E}_\mathrm p=\mathrm m\mathrm g\operatorname\Delta\mathrm h\)

\(\operatorname\Delta{\mathrm E}_\mathrm p=\;\) change in potential energy, \(\mathrm m=\;\) mass, \(\mathrm g\;=\;\) g = acceleration due to gravity, \(\triangle\mathrm h=\) change in vertical distance

\(\mathrm\Sigma\mathrm m{\mathrm v}_{\mathrm b\mathrm e\mathrm f\mathrm o\mathrm r\mathrm e}=\;\mathrm\Sigma\mathrm m{\mathrm v}_{\mathrm a\mathrm f\mathrm t\mathrm e\mathrm r}\)

\(\mathrm\Sigma\mathrm m{\mathrm v}_{\mathrm b\mathrm e\mathrm f\mathrm o\mathrm r\mathrm e}=\;\) vector sum of the momenta of all particles before the collision, \(\mathrm\Sigma\mathrm m{\mathrm v}_{\mathrm a\mathrm f\mathrm t\mathrm e\mathrm r}=\) vector sum of the momenta of all particles after the collision

For elastic collisions:

\(\mathrm\Sigma\frac12\mathrm m\mathrm v_{\mathrm b\mathrm e\mathrm f\mathrm o\mathrm r\mathrm e}^2=\;\mathrm\Sigma\frac12\mathrm m\mathrm v_{\mathrm a\mathrm f\mathrm t\mathrm e\mathrm r}^2\)

\(\mathrm\Sigma\frac12\mathrm m\mathrm v_{\mathrm b\mathrm e\mathrm f\mathrm o\mathrm r\mathrm e}^2=\) sum of the kinetic energies before the collision, \(\mathrm\Sigma\frac12\mathrm m\mathrm v_{\mathrm a\mathrm f\mathrm t\mathrm e\mathrm r}^2=\) sum of the kinetic energies after the collision

Uniformly accelerated motion is described in terms of relationships between measurable scalar and vector quantities, including displacement, speed, velocity and acceleration (ACSPH060)

Representations, including graphs and vectors, and/or equations of motion, can be used qualitatively and quantitatively to describe and predict linear motion (ACSPH061)

Vertical motion is analysed by assuming the acceleration due to gravity is constant near Earth’s surface (ACSPH062)

Newton’s Three Laws of Motion describe the relationship between the force or forces acting on an object, modelled as a point mass, and the motion of the object due to the application of the force or forces (ACSPH063)

Momentum is a property of moving objects; it is conserved in a closed system and may be transferred from one object to another when a force acts over a time interval (ACSPH064)

Energy is conserved in isolated systems and is transferred from one object to another when a force is applied over a distance; this causes work to be done and changes to kinetic and/or potential energy of objects (ACSPH065)

Collisions may be elastic and inelastic; kinetic energy is conserved in elastic collisions (ACSPH066)

#### Waves

**Examples in context**

## Monitoring earthquakes and tsunamis

Major catastrophes like the Japanese and Indian Ocean tsunamis and the Christchurch earthquakes have led to an increased need to monitor and record the plate movements that cause these phenomena. Various devices including seismographs and computer modelling are used to detect, determine the location of and predict effects of earthquakes and tsunamis (ACSPH058). Knowledge of different types of waves and their motion through the ocean and the continents allows prediction of the possible extent of damage or the timing of a tsunami. Earthquake engineering aims to limit seismic risk through design and construction of structures that are better able to resist the effects of earthquakes. A variety of methods including damping and suspension have been developed to protect buildings (ACSPH055).

## Noise pollution and acoustic design

Noise pollution comes from a variety of sources and is often amplified by walls, buildings and other built structures. Acoustical engineering, based on an understanding of the behaviour of sound waves, is used to reduce noise pollution. It focuses on absorbing sound waves or planning structures so that reflection and amplification does not occur (ACSPH058). When new roads are built, consideration is given to noise barrier design, surface materials and speed control. Buildings can be designed to limit the noise that enters from outside sources like roadways and low flying aircraft. Noise mitigation is also achieved by using particular materials for insulation and designing both the interior and exterior to reflect sound in particular ways. Safety equipment such as ear protection is compulsory and extensively tested for use in industrial situations due to the possible health consequences of exposure to excessive noise (ACSPH059).

## Development of the wave theory of light

In the late 17th century, Robert Hooke and Christiaan Huygens published early theories of light as a wave (ACSPH053) and around 1800 Thomas Young showed through experimentation that light passing through a double slit showed interference and thus wave properties. Young also developed principles of coherence and superposition of light. For many years, the presence of the luminiferous aether was proposed as the medium by which light is propagated, an idea that was later disproved by experiments such as the Michelson-Morley experiment (ACSPH054). Later, in the 1860s, James Clerk Maxwell developed a theory of electromagnetism and showed that electromagnetic waves would travel through space at the speed of light, implying light was an electromagnetic wave (ACSPH054).

**Mathematical representations and relationships**

\(\mathrm v=\mathrm f\mathrm\lambda\)

\(\mathrm v=\) speed, \(\mathrm f=\) frequency, \(\mathrm\lambda=\) wavelength

angle of incidence = angle of reflection

\(\mathrm l=\;\mathrm n\frac{\mathrm\lambda}2\) for strings attached at both ends and for pipes open at both ends

\(\mathrm l=\left(2\mathrm n-1\right)\frac{\mathrm\lambda}4\;\) for pipes closed at one end

\(\mathrm n=\) whole numbers 1, 2, 3… relating to the harmonic, \(\mathrm l=\) length of string or pipe, \(\mathrm\lambda=\;\) wavelength of sound wave

\(\mathrm I\propto\frac1{\mathrm r^2}\;\)

\(\;\mathrm I=\) intensity, \(\mathrm r=\) distance from the source

\(\frac{\sin\mathcal i}{\sin\mathrm r}=\;\frac{{\mathrm v}_1}{{\mathrm v}_2}=\frac{{\mathrm\lambda}_1}{{\mathrm\lambda}_2}\)

\(\mathrm i\;=\;\) i = incident angle (relative to the normal), \(\mathrm r\;=\;\) r = angle of refraction (relative to the normal), \({\mathrm v}_1=\) velocity in medium 1, \(\;{\mathrm v}_2=\) velocity in medium 2, \({\mathrm\lambda}_1=\;\) wavelength in medium 1, \({\mathrm\lambda}_{2\;}\) = wavelength in medium 2

Waves are periodic oscillations that transfer energy from one point to another (ACSPH067)

Longitudinal and transverse waves are distinguished by the relationship between the direction of oscillation relative to the direction of the wave velocity (ACSPH068)

Waves may be represented by time and displacement wave diagrams and described in terms of relationships between measurable quantities, including period, amplitude, wavelength, frequency and velocity (ACSPH069)

Mechanical waves transfer energy through a medium; mechanical waves may oscillate the medium or oscillate the pressure within the medium (ACSPH070)

The mechanical wave model can be used to explain phenomena related to reflection and refraction (for example, echoes, seismic phenomena) (ACSPH071)

The superposition of waves in a medium may lead to the formation of standing waves and interference phenomena, including standing waves in pipes and on stretched strings (ACSPH072)

A mechanical system resonates when it is driven at one of its natural frequencies of oscillation; energy is transferred efficiently into systems under these conditions (ACSPH073)

Light exhibits many wave properties; however, it cannot be modelled as a mechanical wave because it can travel through a vacuum (ACSPH074)

A ray model of light may be used to describe reflection, refraction and image formation from lenses and mirrors (ACSPH075)

A wave model explains a wide range of light-related phenomena including reflection, refraction, total internal reflection, dispersion, diffraction and interference; a transverse wave model is required to explain polarisation (ACSPH076)

The speed of light is finite and many orders of magnitude greater than the speed of mechanical waves (for example, sound and water waves); its intensity decreases in an inverse square relationship with distance from a point source (ACSPH077)

## Unit 3: Gravity and electromagnetism

### Unit 3: Gravity and electromagnetism Description

Field theories have enabled physicists to explain a vast array of natural phenomena and have contributed to the development of technologies that have changed the world, including electrical power generation and distribution systems, artificial satellites and modern communication systems. In this unit, students develop a deeper understanding of motion and its causes by using Newton’s Laws of Motion and the gravitational field model to analyse motion on inclined planes, the motion of projectiles, and satellite motion. They investigate electromagnetic interactions and apply this knowledge to understand the operation of direct current (DC) and alternating current (AC) motors and generators, transformers, and AC electricity distribution systems. Students also investigate the production of electromagnetic waves.

Contexts that could be investigated in this unit include technologies such as artificial satellites, navigation devices, large-scale electrical power generation and distribution, motors and generators, electric cars, synchrotron science, medical imaging and astronomical telescopes such as the Square Kilometre Array, and related areas of science and engineering such as sports science, amusement parks, ballistics, forensics, black holes and dark matter.

Through the investigation of appropriate contexts, students explore the ways in which models and theories related to gravity and electromagnetism, and associated technologies, have developed over time and through interactions with social, economic, cultural and ethical considerations. They investigate the ways in which science contributes to contemporary debate about local, regional and international issues, including evaluation of risk and action for sustainability, and recognise the limitations of science to provide definitive answers in different contexts.

Students develop their understanding of field theories of gravity and electromagnetism through investigations of motion and electromagnetic phenomena. Through these investigations they develop skills in relating graphical representations of data to quantitative relationships between variables, using lines of force to represent vector fields, and interpreting interactions in two and three dimensions. They continue to develop skills in planning, conducting and interpreting the results of primary and secondary investigations and in evaluating the validity of primary and secondary data.

### Unit 3: Gravity and electromagnetism Learning Outcomes

By the end of this unit, students:

- understand that motion in gravitational, electric and magnetic fields can be explained using Newton’s Laws of Motion
- understand how the electromagnetic wave model explains the production and propagation of electromagnetic waves across the electromagnetic spectrum
- understand transformations and transfer of energy in electromagnetic devices, as well as transformations and transfer of energy associated with motion in electric, magnetic and gravitational fields
- understand how models and theories have developed over time, and the ways in which physical science knowledge and associated technologies interact with social, economic, cultural and ethical considerations
- use science inquiry skills to design, conduct, analyse and evaluate investigations into uniform circular motion, projectile motion, satellite motion and gravitational and electromagnetic phenomena, and to communicate methods and findings
- use algebraic and graphical representations to calculate, analyse and predict measurable quantities related to motion, gravitational effects and electromagnetic phenomena
- evaluate, with reference to evidence, claims about motion, gravity and electromagnetic phenomena and associated technologies, and justify evaluations
- communicate physics understanding using qualitative and quantitative representations in appropriate modes and genres.

### Unit 3: Gravity and electromagnetism Content Descriptions

#### Science Inquiry Skills

Identify, research and construct questions for investigation; propose hypotheses; and predict possible outcomes (ACSPH078)

Design investigations, including the procedure to be followed, the materials required, and the type and amount of primary and/or secondary data to be collected; conduct risk assessments; and consider research ethics (ACSPH079)

Conduct investigations, including the manipulation of force measurers and electromagnetic devices, safely, competently and methodically for the collection of valid and reliable data (ACSPH080)

Represent data in meaningful and useful ways, including using appropriate SI units, symbols and significant figures; organise and analyse data to identify trends, patterns and relationships; identify sources of uncertainty and techniques to minimise these uncertainties; utilise uncertainty and percentage uncertainty to determine the uncertainty in the result of calculations, and evaluate the impact of measurement uncertainty on experimental results; and select, synthesise and use evidence to make and justify conclusions (ACSPH081)

Interpret a range of scientific and media texts, and evaluate processes, claims and conclusions by considering the accuracy and precision of available evidence; and use reasoning to construct scientific arguments Interpret a range of scientific and media texts, and evaluate processes, claims and conclusions by considering the accuracy and precision of available evidence; and use reasoning to construct scientific arguments (ACSPH082)

Select, construct and use appropriate representations, including text and graphic representations of empirical and theoretical relationships, vector diagrams, free body/force diagrams, field diagrams and circuit diagrams, to communicate conceptual understanding, solve problems and make predictions (ACSPH083)

Select, use and interpret appropriate mathematical representations, including linear and non-linear graphs and algebraic relationships representing physical systems, to solve problems and make predictions (ACSPH084)

Communicate to specific audiences and for specific purposes using appropriate language, nomenclature, genres and modes, including scientific reports (ACSPH085)

#### Science as a Human Endeavour (Units 3 & 4)

ICT and other technologies have dramatically increased the size, accuracy and geographic and temporal scope of datasets with which scientists work (ACSPH086)

Models and theories are contested and refined or replaced when new evidence challenges them, or when a new model or theory has greater explanatory power (ACSPH087)

The acceptance of science understanding can be influenced by the social, economic and cultural context in which it is considered (ACSPH088)

People can use scientific knowledge to inform the monitoring, assessment and evaluation of risk (ACSPH089)

Science can be limited in its ability to provide definitive answers to public debate; there may be insufficient reliable data available, or interpretation of the data may be open to question (ACSPH090)

International collaboration is often required when investing in large-scale science projects or addressing issues for the Asia-Pacific region (ACSPH091)

Scientific knowledge can be used to develop and evaluate projected economic, social and environmental impacts and to design action for sustainability (ACSPH092)

#### Science Understanding

#### Gravity and motion

**Examples in context**

## Forensic science - projectiles

Ballistics is the study of the flight of projectiles, especially bullets. The path of a bullet can be predicted by understanding the effects of air resistance and gravity, and determining the effect of environmental conditions. Scientists study and record the motion of bullets through use of analytical methods such as high speed video analysis and 3D computer modelling (ACSPH086). Databases have been created recording the motion of a variety of bullets from different weapons and computer matching is used to identify weapons used in crimes (ACSPH086). Forensic evidence is often used in court though, despite messages in the popular media, forensic science cannot always provide sufficient conclusive evidence to lead to convictions (ACSPH090).

## Artificial satellites

Artificial satellites are used for communication, research and observation. Knowledge of orbital heights and speeds allow satellites to be best positioned for observation of weather, natural phenomena, traffic and military movements (ACSPH092). Communication via satellite is now used in GPS, satellite phones and television. Orbits and uses of satellites are classified by altitude (Low Earth, Medium Earth or High Earth) and by inclination (equatorial, polar, polar sun-synchronous). Thousands of decommissioned satellites, spent rocket stages and fragments from collisions (collectively called space debris) continue to orbit Earth, causing problems upon collision with functional satellites and posing danger upon re-entry into Earth’s atmosphere. Various strategies including active removal are in place to try to limit an increase in orbiting debris (ACSPH089).

## Developing understanding of planetary motion

Ptolemaic astronomy proposed a geocentric model of the solar system that used the idea of epicycles to explain planetary movement. This model was used until Copernicus proposed a heliocentric model of the solar system (ACSPH087) which was later championed by Galileo, causing conflict with the Catholic church (ACSPH088). Johannes Kepler proposed three laws of planetary motion which form the basis of our modern understanding of orbits. Newton was able to show how these laws were derived from his theory of gravitation (ACSPH087).

**Mathematical representations and relationships**

\(\mathrm w=\mathrm m\mathrm g\)

\(\mathrm w\;=\;\) weight force, \(\mathrm m\;=\;\) mass, \(\mathrm g\;=\;\) acceleration due to gravity (gravitational field strength)

\(\mathrm F=\frac{\mathrm G\mathrm M\mathrm m}{\mathrm r^2}\) and \(\mathrm g=\frac{\mathrm F}{\mathrm m}=\frac{\mathrm G\mathrm M}{\mathrm r^2}\)

\(\mathrm F\;=\;\) gravitational force, \(\mathrm G\;=\;\) G = universal constant of gravitation

\(\left(6.67\;\times\;10^{-11}\;\mathrm N\;\mathrm m^2\;\mathrm k\mathrm g^{-2}\right)\), \(\mathrm M\;=\;\) M = mass of first body, \(\mathrm m\;=\;\) mass of second body, \(\;\mathrm r\;=\;\) separation between the centres of mass of the two bodies, \(\mathrm g\) = acceleration due to gravity

\({\mathrm v}_\mathrm y=\mathrm g\mathrm t+\;{\mathrm u}_\mathrm y\), \(\mathrm y=\;½\;\mathrm g\mathrm t^2+\;{\mathrm u}_\mathrm y\mathrm t\), \({\mathrm v}_\mathrm y^2=2\mathrm g\mathrm y+\;{\mathrm u}_\mathrm y^2\), \({\mathrm v}_{\mathrm x\;}=\;{\mathrm u}_\mathrm x\) and \(\mathrm x=\;{\mathrm u}_\mathrm x\mathrm t\)

\(\mathrm y\;=\) vertical displacement, x = horizontal displacement, \({\mathrm u}_\mathrm y=\;\) initial vertical velocity, \(\;{\mathrm v}_\mathrm y=\;\) vertical velocity at time \(\mathrm t,\;\), \({\mathrm u}_\mathrm x=\) initial horizontal velocity, \({\mathrm v}_\mathrm x\;=\) horizontal velocity at time \(\mathrm t,\;\), \(\mathrm g\;=\) speed of light acceleration due to gravity, \(\mathrm t,\;\) time into flight

\(\mathrm v=\frac{2\mathrm\pi\mathrm r}{\mathrm T}\)

\(\mathrm v=\;\) tangential velocity, \(\;\mathrm T\) = period

\({\mathrm a}_\mathrm c=\frac{\mathrm v^2}{\mathrm r}\)

\({\mathrm a}_\mathrm c\;=\) centripetal acceleration, \(\mathrm v\;=\) tangential velocity, \(\mathrm r\;=\) radius of the circle

\({\mathrm F}_{\mathrm n\mathrm e\mathrm t}=\;\frac{\mathrm m\mathrm v^2}{\mathrm r}\)

\({\mathrm F}_{\mathrm n\mathrm e\mathrm t}=\;\) net force, \(\mathrm m\;=\) mass of body undergoing uniform circular motion, \(\mathrm v=\;\) v= tangential velocity, r = radius of the circle

\(\frac{\mathrm T^2}{\mathrm r^3}=\frac{4\mathrm\pi^2}{\mathrm G\mathrm M}\)

\(\mathrm T\;=\) period of satellite, \(\mathrm M\;=\) mass of the central body, \(\mathrm r\;=\) orbital radius, \(\mathrm G\;=\;\) universal constant of gravitation

\(\left(6.67\;\times\;10^{-11}\;\mathrm N\;\mathrm m^2\;\mathrm k\mathrm g^{-2}\right)\)

The movement of free-falling bodies in Earth’s gravitational field is predictable (ACSPH093)

All objects with mass attract one another with a gravitational force; the magnitude of this force can be calculated using Newton’s Law of Universal Gravitation (ACSPH094)

Objects with mass produce a gravitational field in the space that surrounds them; field theory attributes the gravitational force on an object to the presence of a gravitational field (ACSPH095)

When a mass moves or is moved from one point to another in a gravitational field and its potential energy changes, work is done on or by the field (ACSPH096)

Gravitational field strength is defined as the net force per unit mass at a particular point in the field (ACSPH097)

The vector nature of the gravitational force can be used to analyse motion on inclined planes by considering the components of the gravitational force (that is, weight) parallel and perpendicular to the plane (ACSPH098)

Projectile motion can be analysed quantitatively by treating the horizontal and vertical components of the motion independently (ACSPH099)

When an object experiences a net force of constant magnitude perpendicular to its velocity, it will undergo uniform circular motion, including circular motion on a horizontal plane and around a banked track (ACSPH100)

Newton’s Law of Universal Gravitation is used to explain Kepler’s laws of planetary motion and to describe the motion of planets and other satellites, modelled as uniform circular motion (ACSPH101)

#### Electromagnetism

**Examples in context**

## Medical imaging

Magnetic Resonance Imaging (MRI) uses the property of nuclear magnetic resonance (NMR) to magnetise nuclei inside the body and create clear and accurate images of internal structures. MRI has many advantages over other imaging techniques such as computed tomography (CT) scans and X-rays, including greater contrast between soft tissues (ACSPH086) and an ability to take images without the use of ionising radiation (ACSPH089). Due to the strong magnetic fields used in these machines, there are many safety procedures that must be followed and the procedure is often unsuitable for people with metallic implants or possible allergies to the contrast agents used (ACSPH089).

## The Square Kilometre Array

The Square Kilometre Array (SKA) is a large radio telescope project jointly developed by a number of countries and organisations, which is to be built in multiple countries but primarily Australia, New Zealand and South Africa (ACSPH091). Current information indicates it will be tens of times more sensitive than any other radio instrument, with an ability to survey the sky thousands of times faster. One of the major challenges is the requirement for extremely high data transfer and computing power. Advances in this area will flow through to all areas of everyday computing (ACSPH086). Aims of the project include gathering information to advance our knowledge of dark matter and energy, cosmic magnetism and tests of general relativity, which would not be possible without the SKA (ACSPH086).

## Superconductivity

Superconductivity is the phenomena observed when certain materials are cooled below a characteristic temperature, and zero electrical resistance occurs. Superconductors also exhibit the Meissner effect, where all magnetic flux inside is cancelled. Superconductivity was discovered in 1911 when the resistance of mercury was found to drop to zero at very low temperatures. A series of discoveries caused a number of theories to be put forward to explain the phenomena, but it was not until the late 1950s that a complete atomic scale theory of superconductivity was proposed (ACSPH087). Since then, the development of high-temperature superconductors and practical applications for them have been the focus of research. Superconductors are used in magnetic levitation, such as in maglev trains, mass spectrometers, and in magnetic imaging (MRI). An extremely powerful and large superconducting magnet has been built for use inside the Large Hadron Collider at CERN (ACSPH092).

**Mathematical representations and relationships**

\(\mathrm F=\;\frac1{4\mathrm\pi{\mathrm\varepsilon}_0}\frac{\mathrm Q\mathrm q}{\mathrm r^2}\)

\(\mathrm F=\) force, \(\frac1{4\mathrm\pi{\mathrm\varepsilon}_\mathrm o}=\) Coulomb constant

\(\left(9\;\times\;10^9\;\mathrm N\;\mathrm m^2\;\mathrm C^{-2}\right)\), \(\mathrm q\;=\) charge on the first object, \(\mathrm Q\;=\) charge on the second object, \(\mathrm r\;=\) separation between the charges

\(\mathrm E=\frac{\mathrm F}{\mathrm q}=\frac1{4\mathrm\pi{\mathrm\varepsilon}_0}\frac{\mathrm q}{\mathrm r^2}\)

\(\mathrm E\;=\) electric field strength, \(\mathrm F\;=\;\) force, \(\mathrm q\;=\) charge, \(\mathrm r\;=\) distance from the charge, \(\;\frac1{4\mathrm\pi{\mathrm\varepsilon}_\mathrm o}=\) Coulomb constant

\(\left(9\;\times\;10^9\;\mathrm N\;\mathrm m^2\;\mathrm C^{-2}\right)\)

\(\mathrm V=\frac{\mathrm\Delta\mathrm U}{\mathrm q}\)

\(\mathrm V\;=\) electrical potential difference, \(\mathrm\Delta\mathrm U\;=\) change in potential energy, \(\mathrm q\;=\) charge

\(\mathrm B=\frac{µ_\mathrm o\mathrm I}{2\mathrm\pi\mathrm r}\)

\(\mathrm B\;=\) magnetic flux density, \(\mathrm I\;=\) current in wire, \(\mathrm r\;=\) distance from the centre of the wire, \(\;\frac{µ_\mathrm o}{2\mathrm\pi}=\) magnetic constant

\(\text{(2 × }10^{-7}\text{T }\text{A}^{-1}\text{m)}\)

For a straight, current carrying wire perpendicular to a magnetic field \(\mathrm F=\mathrm B\mathrm I\mathrm l\)

\(\mathrm B\;=\) magnetic flux density, \(\mathrm F=\) force on the wire, \(\mathrm l=\) l=length of wire in the magnetic field, \(\mathrm I\) = current in the wire

For a charge moving perpendicular to a magnetic field \(\mathrm F=\mathrm q\mathrm v\mathrm B\)

\(\mathrm F=\) force on a charge moving in an applied magnetic field, \(\mathrm q\;=\) charge, \(\mathrm v=\;\) velocity of the charge, \(\mathrm B\;=\) magnetic flux density

\(\mathrm\phi=\mathrm B{\mathrm A}_\perp\)

\(\mathrm\phi=\;\) magnetic flux, \({\mathrm A}_\perp=\;\) area of current loop perpendicular to the applied magnetic field, \(\mathrm B\;=\) magnetic flux density

\(\mathrm e\mathrm m\mathrm f=-\;\frac{\mathrm n\bigtriangleup(\mathrm B{\mathrm A}_\perp)}{\operatorname\Delta\mathrm t}=-\;\mathrm n\frac{\operatorname\Delta\mathrm\phi}{\operatorname\Delta\mathrm t}\)

\(\mathrm e\mathrm m\mathrm f=\) induced potential difference, \(\triangle\mathrm\phi\;=\) change in magnetic flux, \(\mathrm n\;=\) number of windings in the loop, \({\mathrm A}_\perp=\;\) area of current loop perpendicular to the applied magnetic field, \(\operatorname\Delta\mathrm t\;=\) time interval over which the magnetic flux change occurs, \(\mathrm B\;=\) magnetic flux density

\(\frac{{\mathrm V}_\mathrm p}{{\mathrm V}_\mathrm s}=\frac{{\mathrm n}_\mathrm p}{{\mathrm n}_\mathrm s}\)

\({\mathrm V}_\mathrm p=\) potential difference across the primary coil, \(\;{\mathrm V}_\mathrm s=\;\) Vs= potential difference across the secondary coil, \({\mathrm n}_\mathrm p\;=\) number of turns on primary coil, \({\mathrm n}_\mathrm s=\) number of turns on secondary coil

\({\mathrm I}_\mathrm p{\mathrm V}_\mathrm p={\mathrm I}_\mathrm s{\mathrm V}_\mathrm s\;\)

\({\mathrm I}_\mathrm p=\) current in primary coil, \({\mathrm V}_\mathrm p=\;\) Vp= potential difference across primary coil, \({\mathrm I}_\mathrm s\) = current in secondary coil, \(\;{\mathrm V}_\mathrm s\) = potential difference across secondary coil

Electrostatically charged objects exert a force upon one another; the magnitude of this force can be calculated using Coulomb’s Law (ACSPH102)

Point charges and charged objects produce an electric field in the space that surrounds them; field theory attributes the electrostatic force on a point charge or charged body to the presence of an electric field (ACSPH103)

A positively charged body placed in an electric field will experience a force in the direction of the field; the strength of the electric field is defined as the force per unit charge (ACSPH104)

When a charged body moves or is moved from one point to another in an electric field and its potential energy changes, work is done on or by the field (ACSPH105)

Current-carrying wires are surrounded by magnetic fields; these fields are utilised in solenoids and electromagnets (ACSPH106)

The strength of the magnetic field produced by a current is called the magnetic flux density (ACSPH107)

Magnets, magnetic materials, moving charges and current-carrying wires experience a force in a magnetic field; this force is utilised in DC electric motors (ACSPH108)

Magnetic flux is defined in terms of magnetic flux density and area (ACSPH109)

A changing magnetic flux induces a potential difference; this process of electromagnetic induction is used in step-up and step-down transformers, DC and AC generators, and AC induction motors (ACSPH110)

Conservation of energy, expressed as Lenz’s Law of electromagnetic induction, is used to determine the direction of induced current (ACSPH111)

Electromagnetic waves are transverse waves made up of mutually perpendicular, oscillating electric and magnetic fields (ACSPH112)

Oscillating charges produce electromagnetic waves of the same frequency as the oscillation; electromagnetic waves cause charges to oscillate at the frequency of the wave (ACSPH113)