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2026 QCE Physics exam: What to learn from last year's mistakes
Hi all, in preparation for the upcoming exam, here's what to learn from last year's mistakes.
2025 exam median and average: not stated in QCAA's report.
The General exam was 101 raw marks and worth 50% of the subject result. Paper 1 had 51 marks; Paper 2 had 50.
I've gone through the report and guide. These questions are worth redoing with your working visible, especially the units.
QCAA doesn't publish written-question averages. The sections below explain how an answer misses the criteria, not how many students made each error.
Paper 1, Q23b: Saturn's orbital period
4 marks.
Where an answer loses marks: Mixing years and seconds or applying the wrong power when rearranging Kepler's third law.
What you needed: Convert one Earth year to 31,536,000 s. Then use Tₛ²/rₛ³ = Tₑ²/rₑ³, with radii 1.43 × 10¹² m and 1.49 × 10¹¹ m. Rearranging gives Tₛ = Tₑ(rₛ/rₑ)^(3/2), approximately 9.4 × 10⁸ s. The time conversion earned its own mark.
Paper 1, Q24a: Why brighter light isn't enough
5 marks.
Where an answer loses marks: Saying light is made of photons without explaining the threshold frequency, or claiming brightness increases the energy of each photon.
What you needed: Each photon has energy E = hf. An electron needs enough energy to escape the metal. At a fixed frequency, greater intensity means more photons, not more energy per photon. Below the threshold frequency, increasing intensity still doesn't eject electrons in the model tested here. Explain why that contradicts the classical expectation of electrons gradually accumulating sufficient wave energy.
Paper 1, Q24b: Work function
4 marks.
Where an answer loses marks: Adding the kinetic energy to hf, or writing a joule value with eV beside it.
What you needed: Rearrange Eₖ = hf − W to W = hf − Eₖ. The calculation gives approximately 1.38 × 10⁻¹⁹ J. Divide by 1.602 × 10⁻¹⁹ J per eV to get about 0.863 eV. The unit conversion is a separate mark.
Paper 1, Q25a and b: Projectile data
2 marks in a; 5 in b.
Where an answer loses marks: Giving the memorised 45° range result instead of reading this experiment's graph.
What you needed: In part a, range increases up to 30° and then decreases. For part b, use the 80° launch: uₓ = 3.0cos80° ≈ 0.52 m/s. Read the horizontal range as 0.50 m, then t = range/uₓ ≈ 0.96 s. Use the graph's actual conditions rather than assuming launch and landing heights are equal.
For 2026, perusal time is five minutes instead of ten. Conservation of lepton number and baryon number is explicitly included, and the formula book has changed.
Use the 2025 report alongside official marking guide. 2026 syllabus changes.
Figures and criteria: QCAA. Explanations paraphrased from its materials, © State of Queensland (QCAA) 2025–2026, CC BY 4.0.
Use the Physics hub and past papers and marking guides alongside this.
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