Skip to main content

← WACE

WA · SCSA2026

WACE Physics: complete 2026 guide to ATAR Units 3 and 4 (SCSA)

A complete 2026 guide to WACE ATAR Physics Units 3 and 4 (SCSA, Western Australia). How the course is assessed (50 percent school-based, 50 percent external written examination), what each unit covers, and links to every dot-point answer we have for Unit 3 (Gravity and electromagnetism) and Unit 4 (Wave models and quantum physics).

Browse guides →Syllabus dot points (33)ATAR calculator

WACE ATAR Physics (Western Australia, SCSA) Year 12 is the Units 3 and 4 sequence. The final ATAR course mark is split evenly: 50 percent school-based assessment across the year and 50 percent a single external written examination set and marked by SCSA at the end of Year 12. The external paper covers Units 3 and 4 together, so Unit 3 content sat early in the year remains examinable in November.

This page is the index. Below you will find the structure of the course, how the marks combine, and links to every dot-point answer we have written for WACE Physics Units 3 and 4.

How the course is assessed in 2026

School-based assessment: 50 percent. Run by your school against the SCSA assessment outline, this combines written tests, science inquiry (practical investigations and data analysis) and school examinations. It is moderated against the external examination so that schools mark to a common standard.

External examination: 50 percent. A single written paper of about three hours, set and marked centrally by SCSA, covering Units 3 and 4 together. It blends short-answer and extended-answer questions across calculations, explanations, graph and data interpretation, and evaluation of experimental work. A Formulae and Data Sheet and a Periodic Table are supplied.

The two halves are combined and statistically moderated to produce your final ATAR course mark, which then feeds into your ATAR through the usual scaling process.

Unit 3: Gravity and electromagnetism

Unit 3 develops field thinking. You model gravity as a field that governs projectile, circular and orbital motion, then move to electric and magnetic fields and the forces they exert on charges and currents, finishing with electromagnetic induction, which links the two.

Topics. Gravitation and orbital motion (projectile motion, uniform circular motion, Newton's law of universal gravitation, satellites and Kepler's third law). Electric fields and potential (Coulomb's law, uniform fields between parallel plates, work and potential difference). Magnetism and moving charges (force on a moving charge and on a current-carrying conductor, the motor effect). Electromagnetic induction (magnetic flux, Faraday's and Lenz's laws, generators and transformers).

Unit 4: Wave models and quantum physics

Unit 4 moves from waves to the quantum description of light and matter, then to the structure of the atom and nucleus.

Topics. Wave motion and superposition (the wave equation, standing waves, resonance and beats). Light as a wave (diffraction, two-slit interference, the electromagnetic spectrum). The photoelectric effect and photons (the particle model of light, work function and threshold frequency). Atomic and nuclear physics (atomic energy levels and spectra, the Standard Model, mass-energy equivalence, nuclear reactions and radioactivity).

Our 2026 WACE Physics dot-point answers

Every link below is a focused answer to one SCSA syllabus content point. Each page identifies what the dot point is asking, gives the worked answer with the relevant physics and a numeric example, and flags the mistake most likely to cost marks.

Unit 3: Gravity and electromagnetism

Unit 4: Wave models and quantum physics

The WACE system, explained

See all →

Common questions about Physics

How is WACE ATAR Physics assessed in 2026?
The Year 12 ATAR Physics course mark is 50 percent school-based assessment and 50 percent a single external written examination set and marked by SCSA. The school-based component is made up of tests, science inquiry (practical investigations) and an examination component run by your school. The external examination covers Units 3 and 4 together at the end of the year and is the single largest piece of assessment.
What do Units 3 and 4 cover?
Unit 3 is Gravity and electromagnetism. It covers gravitation and orbital motion (including projectile and circular motion), electric fields and potential, magnetism and the force on moving charges, and electromagnetic induction. Unit 4 is Wave models and quantum physics. It covers wave motion and superposition, light as a wave (diffraction, interference, the electromagnetic spectrum), the photoelectric effect and photons, and atomic and nuclear physics (energy levels, the Standard Model, mass-energy and nuclear reactions).
What is the structure of the external WACE Physics exam?
The external written examination is a single paper of about three hours testing Units 3 and 4 together. It typically has a short-answer section and an extended-answer section, with questions spanning calculations, explanations, graph and data interpretation, and analysis of experimental work. A formula sheet and a periodic table or constants sheet are provided. The paper is worth 50 percent of the final ATAR course mark.
Is the formula sheet provided in the exam?
Yes. SCSA provides a Formulae and Data Sheet and a Periodic Table with the external examination, so you are not required to memorise constants such as G, the elementary charge, Planck's constant or the speed of light. You are still expected to know which formula to select, how to rearrange it, and how to combine relationships, because the sheet lists formulae without explaining when each one applies.
Do I need ATAR Physics for engineering and science at WA universities?
ATAR Physics is a prerequisite or strongly recommended for most engineering pathways (mechanical, civil, electrical, aerospace, mining, mechatronic) at UWA, Curtin, ECU and Murdoch, and for physics, astrophysics and many physical-science majors. It is recommended for some IT, architecture and surveying degrees. Always confirm current prerequisites with TISC and the individual university.
How important is the science inquiry (practical) work?
Science inquiry skills are assessed within the school-based component and are also examinable in the external paper, where questions ask you to evaluate method, identify variables, process data, draw graphs and discuss reliability and validity. Practical investigations in Year 12 build the data-handling and uncertainty skills the exam rewards, so treat them as exam preparation rather than separate coursework.
How do I approach projectile motion problems?
Split the motion into horizontal (constant velocity) and vertical (constant acceleration due to gravity). Use t as the shared variable across both axes.
What's the difference between work and power?
Work (J) is energy transferred by a force over a distance. Power (W) is the rate of doing work — work divided by time.
When is momentum conserved?
In any collision (elastic or inelastic) where no external net force acts on the system. Kinetic energy is only conserved in elastic collisions.
What's the photoelectric effect?
Light shone on a metal can eject electrons, but only if the photon energy (hf) exceeds the work function. The kinetic energy of the ejected electron is hf - W. Evidence that light behaves as discrete quanta (photons).
How do magnetic forces on current-carrying wires work?
F = BIL sin θ for a wire in a uniform field B with current I and length L. Direction comes from the right-hand rule. Underpins motors, generators, and ammeters.