QCE Physics 2023

Walkthrough of the 2023 QCE physics exam: what it assessed, strategy tips, and the common errors flagged in the official marker report.

Marks: 60
Time: 120 min
Authority: QCAA
Updated: 2026-05-29

Open the official PDF ->Official marking notes

What this paper assessed

The QCE Physics external assessment (Paper, worth 50% of the Unit 3 & 4 result) drew on the Unit 3 and Unit 4 content of the QCAA syllabus:

Unit 3 - Gravity and electromagnetism: projectile and circular motion, gravitational fields and orbits, electric and magnetic fields, the motor effect, and electromagnetic induction (Faraday's and Lenz's laws).
Unit 4 - Revolutions in modern physics: special relativity (time dilation, length contraction, mass-energy), quantum physics and the photoelectric effect, and the Standard Model.

Many items required students to extract data from a graph, apply a relationship, then comment on the limitations of the model. The paper rewarded structured reasoning, correct units, and naming the law being applied before describing an effect.

Structure and timing

The paper is 60 marks in 120 minutes, plus 5 minutes perusal time.

Section 1 - multiple choice (~20 marks): target ~30 minutes (about 1.5 min/question).
Section 2 - short response (~40 marks): target ~90 minutes at roughly 2.25 minutes per mark.

A 4-mark calculation deserves ~9 minutes. List the formula, the substituted values, and the answer with units on separate lines. Reserve ~10 minutes to check units and significant figures, and use perusal time to scan graph-based items.

Worked practice questions (exam-style)

Worked example

Question 1 (4 marks): A ball is thrown horizontally from a cliff at $15\ \text{m s}^{-1}$ and lands after 2.0 s. Calculate (a) the horizontal distance travelled and (b) the vertical velocity on impact. (Take $g = 9.8\ \text{m s}^{-2}$ .)

Resolve into independent horizontal and vertical components.

(a) Horizontal (constant velocity): $s_x = u_x t = 15 \times 2.0 = 30\ \text{m}$ .
(b) Vertical (uniform acceleration, $u_y = 0$ ):

v_y = u_y + g t = 0 + 9.8 \times 2.0 = 19.6\ \text{m s}^{-1}\ \text{(downward)}

The horizontal and vertical motions are independent; gravity acts only vertically.

Worked example

Question 2 (5 marks): A bar magnet is pushed north-pole-first into a coil connected to a galvanometer. Using Faraday's and Lenz's laws, explain the direction of the induced current and why a force opposes the magnet's motion.

Faraday's law: the changing magnetic flux through the coil, $\varepsilon = -N\dfrac{d\Phi}{dt}$ , induces an EMF and hence a current.
Lenz's law: the induced current flows so its magnetic field opposes the increase in flux - the coil's near face becomes a north pole to repel the approaching magnet.
Opposing force: this repulsion means the experimenter must do work to push the magnet in; that work is converted to electrical energy in the coil, satisfying conservation of energy.
A faster push gives a greater $\dfrac{d\Phi}{dt}$ and a larger induced current.

Worked example

Question 3 (5 marks): A muon travels at $v = 0.95c$ relative to the ground. Its proper lifetime is $2.2\ \mu\text{s}$ . Calculate the lifetime measured by a ground observer and explain the significance for muon detection at sea level.

The proper lifetime $t_0 = 2.2\ \mu\text{s}$ is measured in the muon's rest frame. Apply time dilation:

t = \frac{t_0}{\sqrt{1 - \dfrac{v^2}{c^2}}}

The Lorentz factor:

\gamma = \frac{1}{\sqrt{1 - 0.95^2}} = \frac{1}{\sqrt{1 - 0.9025}} = \frac{1}{\sqrt{0.0975}} = \frac{1}{0.312} = 3.20

So:

t = 3.20 \times 2.2 = 7.0\ \mu\text{s}\ (2\ \text{s.f.})

Significance: the dilated lifetime is long enough for muons created high in the atmosphere to reach sea-level detectors - direct experimental evidence for special relativity.

Common errors students made

Recurring errors in QCE Physics responses include:

Missing or inconsistent units in calculations and final answers.
Mixing scalar and vector quantities (e.g. speed vs velocity, distance vs displacement).
Treating projectile motion as one-dimensional rather than resolving into components.
Forgetting that induced EMF depends on the rate of change of flux, not flux itself.

Add these subject-specific traps:

In Lenz's-law items, stating a direction without linking it to opposing the flux change and to energy conservation.
Confusing proper time and dilated time in relativity problems.
Reporting answers to too many significant figures, or dropping a negative sign/direction in field problems.
Misreading the QCAA cognition verb - describing where "analyse" or "evaluate" is required.

How to use this paper

Sit Section 1 in 30 minutes and Section 2 in 90 minutes under timed conditions with the formula and data sheet. Mark against the QCAA marking guide and published assessment report (linked in the frontmatter), which show where method and reasoning marks sit. Rebuild every calculation that lost a method mark from a clean start, listing formula, substitution and unit-checked answer on separate lines. Keep an error log mapping each lost mark to a syllabus subject-matter point, and re-attempt graph-interpretation items under time pressure after a 48-hour gap.

Use this paper well

Sit the paper under exam conditions (120 minutes, 60 marks).
Mark yourself against the official QCAA marking notes.
Compare against the Physics hub to find the syllabus dot points this paper tested.

What this paper assessed

Structure and timing

Worked practice questions (exam-style)

Common errors students made

How to use this paper

Use this paper well

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