QCE Physics Paper 1 free practice questions with answers
Read question 1 and its full worked answer from paper 1 of our 20-paper QCE Physics Paper 1 set, then download the 4-page PDF. These are original practice questions, not official past papers. Page updated 3 November 2026.
An electron is accelerated from rest through a potential difference of 5700 V. (h = 6.626
× 10−³⁴ J s, me = 9.109 × 10−³¹ kg, e = 1.602 × 10−¹⁹ C.) What is the de Broglie wavelength of the electron?
A 7.26 × 10−¹⁹ m
B 1.62 × 10−¹¹ m
C 2.70 × 10−⁵⁶ m
D 3.25 × 10−¹¹ m
Correct answer: B — 1.62 × 10−¹¹ m
- Kinetic energy gained: ½mv² = eV, so momentum p = √(2meV) = 4.08 × 10−²³ kg m s−¹.
- λ = h ÷ p = 6.626 × 10−³⁴ ÷ 4.08 × 10−²³ = 1.62 × 10−¹¹ m
- Why the other options are wrong:
- A (7.26 × 10−¹⁹ m): used energy instead of momentum
- C (2.70 × 10−⁵⁶ m): multiplied by the momentum
- D (3.25 × 10−¹¹ m): doubled the wavelength de Broglie wavelength λ = h/p: matter has wave properties, and a bigger momentum means a shorter wavelength.
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What is in the QCE Physics Paper 1 free sample?
The first 3 questions from paper 1 of the set, in the real exam layout, followed by the step-by-step worked answers. It is a 4-page PDF; this page shows question 1 with its answer.
How many full QCE Physics Paper 1 papers are there?
20 original papers for Queensland Year 12 students (QCE). Each is a 50-mark paper with Section I 20 multiple-choice, Section II 30 marks, 10 minutes perusal and 90 minutes working time, with a worked solution for every question. Papers start at A$15.99 and download instantly as a PDF.
Are these official past papers?
No. The sample is taken from our own original practice paper and is not an official past paper or affiliated with any exam authority.