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QLDPhysics2022

QCE Physics 2022

Walkthrough of the 2022 QCE physics exam: what it assessed, strategy tips, and the common errors flagged in the official marker report.

Marks
97
Time
180 min
Authority
QCAA
Updated
Open the official PDF Official marking notes
Key fact

This paper was set on the 2019 QCAA syllabus. From the 2026 external assessments the 2025 syllabus applies, so some content and the exam format have changed. It is still useful practice, but check the current QCAA Physics syllabus and QCAA's 2026 key changes before relying on it. The mark and timing figures at the top of this page are a guide based on the 2024 papers (two papers, each with 90 minutes of working time), not QCAA's official structure for every year. Marks and question types vary, so use QCAA's own paper.

What this paper assessed

The QCAA Physics external assessment (worth 50% of the subject) covers Units 3 and 4. The 2022 paper assessed:

  • Unit 3 - Gravity and electromagnetism: gravitational fields and orbital motion, projectile motion, electric fields and charged particles, and magnetic fields and the motor effect.
  • Unit 4 - Revolutions in modern physics: special relativity, the quantum nature of light (the photoelectric effect), the standard model of particle physics, and the structure of the atom/nucleus.

Many items required students to extract data from a graph, apply a relationship, and then comment on the limitations of the model or assumptions. The extended response rewarded structured reasoning - naming the relevant law and applying it step by step - over volume of writing.

Structure and timing

QCAA sets the external assessment as more than one paper, and the number of marks, the sections and the question types differ from year to year. Open the official paper for the exact structure of this year; the marks and time shown at the top of this page are a guide only.

  • Pace by marks. Share your working time in proportion to the marks on offer, so a 6-mark item gets about three times the time of a 2-mark item. Flag any multiple choice item that runs long and return to it.
  • Use perusal time. Scan for the data-heavy items and the longest calculations or extended responses so you can plan them early.
  • Subject habits. Set out every calculation on three lines: the relationship, the substituted values with units, and the final answer with units and appropriate significant figures. For graph-based items, mark the gradient and intercept on the page before stating their physical meaning, and keep a few minutes at the end to check units, vector directions and significant figures.

Worked practice questions (exam-style)

Worked example

Question 1 (5 marks): Projectile motion

A projectile is launched horizontally at 15 m s−115\ \text{m s}^{-1} from a cliff 20 m20\ \text{m} high. Taking g=9.8 m s−2g = 9.8\ \text{m s}^{-2} and ignoring air resistance, find the time of flight and the horizontal distance travelled.

Solution. Treat horizontal and vertical motion independently. Vertically, initial vertical velocity is 00; using s=12gt2s = \tfrac{1}{2}gt^2:

20=12(9.8)t2  ⟹  t2=409.8=4.08  ⟹  t=2.02 s20 = \tfrac{1}{2}(9.8)t^2 \implies t^2 = \frac{40}{9.8} = 4.08 \implies t = 2.02\ \text{s}

(2 marks.) Horizontally there is no acceleration, so

x=ux t=15×2.02=30.3 mx = u_x \, t = 15 \times 2.02 = 30.3\ \text{m}

(2 marks.) Final answers with units (1 mark). The key principle: horizontal and vertical components are independent, and the time of flight is set by the vertical drop alone.

Worked example

Question 2 (6 marks): Electromagnetic induction

A coil of NN turns experiences a uniform magnetic flux that decreases from 0.040 Wb0.040\ \text{Wb} to 0.010 Wb0.010\ \text{Wb} in 0.050 s0.050\ \text{s}. For N=250N = 250, calculate the average induced EMF, and explain why no EMF is induced once the flux becomes steady.

Solution. By Faraday's law the magnitude of the average induced EMF is

∣ε∣=N∣ΔΦΔt∣=250×∣0.010−0.040∣0.050|\varepsilon| = N\left|\frac{\Delta\Phi}{\Delta t}\right| = 250 \times \frac{|0.010 - 0.040|}{0.050}

(2 marks for the relationship and substitution). Then

∣ε∣=250×0.0300.050=250×0.60=150 V|\varepsilon| = 250 \times \frac{0.030}{0.050} = 250 \times 0.60 = 150\ \text{V}

(2 marks for the answer with units). Once the flux is steady, ΔΦΔt=0\dfrac{\Delta\Phi}{\Delta t} = 0, so the induced EMF is zero - induction depends on the rate of change of flux, not on the magnitude of the flux itself (2 marks).

Worked example

Question 3 (5 marks): Special relativity - time dilation

A spacecraft travels at 0.80c0.80c relative to Earth. An onboard clock measures a journey time of 3.03.0 years (proper time). Calculate the time elapsed as measured by an observer on Earth.

Solution. The proper time t0=3.0t_0 = 3.0 years is measured in the spacecraft frame. The Earth observer measures the dilated time

t=t01−v2c2t = \frac{t_0}{\sqrt{1 - \dfrac{v^2}{c^2}}}

(1 mark for the relationship). With v=0.80cv = 0.80c, v2c2=0.64\dfrac{v^2}{c^2} = 0.64, so

1−0.64=0.36=0.60\sqrt{1 - 0.64} = \sqrt{0.36} = 0.60

(2 marks). Therefore

t=3.00.60=5.0 yearst = \frac{3.0}{0.60} = 5.0\ \text{years}

(1 mark). The Earth observer measures the longer time (1 mark) - moving clocks run slow, so the journey appears to take 5.0 years from Earth.

Common errors students made

The 2022 QCAA marker report flagged missing units, mixing scalar and vector quantities, treating projectile motion as one-dimensional, and students forgetting that induced EMF depends on the rate of change of flux rather than on flux itself. Add these recurring traps:

  • Combining horizontal and vertical motion incorrectly - using the resultant velocity in a vertical-only equation, or forgetting the horizontal velocity is constant.
  • Misusing the Lorentz factor - inverting the dilation formula, or confusing proper time with the observer's measured time.
  • No law named - stating an outcome (e.g. "the EMF is induced") without identifying Faraday's/Lenz's law and applying it.
  • Significant figures and units dropped at the final step, or scalar magnitudes reported where a vector direction is required.

How to use this paper

The 2022 sitting was two papers of 90 minutes working time each, with 10 minutes of perusal in the booklets. QCAA's 2026 timetable has two papers, each with 5 minutes of perusal and 90 minutes of working time (check the current QCAA syllabus for your sitting). Sit one paper at a time under timed conditions, pacing each by marks. Use only the QCAA data and formula sheet and a calculator. Mark against the official QCAA marking guide and marker report (linked at the top of this page) to see where method and reasoning marks fall. Re-attempt any extended-response item scoring below half, structuring it as named-law → applied relationship → result-with-units. Keep a formula-to-concept sheet (Faraday's law, time dilation, projectile components) and a checklist of units and vector directions to apply before submitting each answer.

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