Skill Align QCE Physics - Free Online Pack 0 Paper 1
An independently authored QCE Physics practice paper with worked answers and question-specific marking guidance.
- Paper
- Paper 1 Combined Independent Practice Book
- Reading
- 5 minutes perusal
- Writing
- 90 minutes
- Assessment
- 51 marks
The current QCAA Physics formula and data book is supplied separately. A QCAA-approved scientific or graphics calculator may be used.
Section 1 - Multiple-choice questions
Questions 1-20 are multiple choice. Select the best answer for each question. Each question is worth 1 mark.
Question 1
1 mark- Its vertical velocity is zero, its horizontal velocity is unchanged and its acceleration is downward.
- Both its velocity and acceleration are zero.
- Its horizontal velocity is zero and its vertical velocity is greatest.
- Its acceleration is horizontal because the path is curved.
Question 2
1 mark- +1.0 x 10^-4 J
- -1.0 x 10^-4 J
- -2.5 x 10^-8 J
- +2.5 x 10^7 J
Question 3
1 mark- The interval measured only in the frame where both events occur at different positions.
- The largest reading from any two synchronised clocks.
- The interval measured by one clock present at both events.
- An interval that is identical in every inertial frame.
Question 4
1 mark- The maximum kinetic energy doubles, but the emission rate is unchanged.
- Both stopping potential and maximum kinetic energy double.
- Emission stops because each photon now has half the energy.
- The emission rate increases, but the maximum photoelectron kinetic energy is unchanged.
Question 5
1 mark- uud
- udd
- uuu
- ddu
Question 6
1 mark- It becomes three times as large.
- It becomes one-third as large.
- It becomes nine times as large.
- It is unchanged because the radius is unchanged.
Question 7
1 mark- South
- North
- Up
- East
Question 8
1 mark- The flashes must be simultaneous because light has the same speed in all frames.
- Only one flash can be observed because the observer is moving.
- The earlier flash is determined solely by which lamp is brighter.
- The flashes need not be simultaneous because the observer's frame assigns different times to separated events.
Question 9
1 mark- eh
- h/e
- the work function only
- the speed of light
Question 10
1 mark- A down quark changes into an up quark.
- An up quark changes into a down quark.
- All three quarks annihilate into photons.
- A lepton changes into a baryon.
Question 11
1 mark- The second experiences four times the field strength and four times the force.
- The first experiences four times the field strength because it is easier to accelerate.
- Both experience the same force because they occupy the same point.
- They experience the same gravitational-field strength, although the second experiences four times the force.
Question 12
1 mark- The near face acts as a south pole to increase the magnet's speed.
- No current is induced until the magnet passes through the loop.
- The near face of the loop acts as a north pole to oppose the increasing flux.
- The induced field is always in the same direction as the magnet's field.
Question 13
1 mark- 1.25
- 0.60
- 2.78
- 1.67
Question 14
1 mark- It doubles.
- It becomes four times as large.
- It halves.
- It is unchanged because the particle's charge is unchanged.
Question 15
1 mark- 0 before and 0 after
- 1 before and 1 after
- 0 before and 2 after
- 1 before and 0 after
Question 16
1 mark- 4
- 8
- 16
- 2
Question 17
1 mark- 1/4
- 4
- 1/16
- 16
Question 18
1 mark- 9.0 x 10^13 J
- 9.0 x 10^10 J
- 3.0 x 10^2 J
- 1.1 x 10^-11 J
Question 19
1 mark- Star X has the lower surface temperature.
- The stars must have equal temperature but different radii.
- Peak wavelength gives only distance, not temperature.
- Star X has the higher surface temperature.
Question 20
1 mark- They produce two photons travelling in different directions.
- They produce one stationary photon.
- They produce a single proton with no other products.
- They merge into a neutrino with electric charge -1.
Section 2 - Short-response questions
Questions 21-25 are short response. Answer every part, show relevant working and use the supplied evidence where required.
Question 21
3 marksA rescue flare is launched from a platform 2.00 m above sea level at 28.0 m s^-1 and 35.0 degrees above the horizontal. Air resistance is negligible.
Question 22
3 marksA straight 0.180 m rail segment carries 3.50 A east through a uniform 0.420 T magnetic field directed vertically downward.
Question 23
5 marksA muon has a proper mean lifetime of 2.20 microseconds and moves through the laboratory at 0.960c.
Question 24
9 marksMonochromatic light illuminates a clean metal. Measured frequency f and stopping potential V_s are: (6.0 x 10^14 Hz, 0.30 V), (7.0 x 10^14 Hz, 0.71 V), (8.0 x 10^14 Hz, 1.12 V), (9.0 x 10^14 Hz, 1.54 V). Treat the trend as linear.
Question 25
11 marksA free neutron initially at rest undergoes beta-minus decay: n -> p + e- + anti-nu_e. Use the Standard Model and the 2026 conservation-law requirements.
Worked Solutions And Marking Guide
General marking principles
- Award each listed mark independently when the required physical relationship, working step or evidence statement is demonstrated.
- Accept physically correct equivalent wording and logically equivalent calculations with appropriate units.
- Carry forward a candidate's earlier numerical value when later working is physically consistent, unless the resulting answer is impossible.
Section 1 Question 1
Answer: Its vertical velocity is zero, its horizontal velocity is unchanged and its acceleration is downward.
Gravity continues to provide downward acceleration at the apex, while the absence of horizontal force leaves the horizontal velocity unchanged.
Section 1 Question 2
Answer: -1.0 x 10^-4 J
Using Delta U = q Delta V gives (2.0 x 10^-6)(-50) = -1.0 x 10^-4 J, so electric potential energy decreases.
Section 1 Question 3
Answer: The interval measured by one clock present at both events.
Proper time is recorded by a single clock following the worldline through both events; other inertial frames measure a dilated interval.
Section 1 Question 4
Answer: The emission rate increases, but the maximum photoelectron kinetic energy is unchanged.
Doubling intensity supplies more photons per second. Each photon still has energy hf, so the maximum kinetic energy and stopping potential do not change.
Section 1 Question 5
Answer: uud
Two up quarks and one down quark have charge +2/3 +2/3 -1/3 = +1, the proton charge.
Section 1 Question 6
Answer: It becomes nine times as large.
The relationship F = mv^2/r makes the force proportional to the square of speed, so a factor of three in speed gives a factor of nine in force.
Section 1 Question 7
Answer: North
The right-hand rule for I cross B gives east crossed with downward, which points north.
Section 1 Question 8
Answer: The flashes need not be simultaneous because the observer's frame assigns different times to separated events.
Special relativity makes simultaneity frame-dependent for spatially separated events, even though every inertial observer measures the same light speed.
Section 1 Question 9
Answer: h/e
From eV_s = hf - phi, V_s = (h/e)f - phi/e, so the gradient is Planck's constant divided by elementary charge.
Section 1 Question 10
Answer: A down quark changes into an up quark.
A neutron udd becomes a proton uud when one down quark changes to an up quark through the weak interaction.
Section 1 Question 11
Answer: They experience the same gravitational-field strength, although the second experiences four times the force.
Field strength is a property of the source and position. Since F = mg, increasing the test mass by four increases force by four without changing g.
Section 1 Question 12
Answer: The near face of the loop acts as a north pole to oppose the increasing flux.
Lenz's law requires the induced field to oppose the increase in magnetic flux, so the approaching north pole is repelled by a north face.
Section 1 Question 13
Answer: 1.67
Gamma = 1/sqrt(1 - 0.80^2) = 1/sqrt(0.36) = 1.67, so relativistic time and length effects are significant.
Section 1 Question 14
Answer: It halves.
The de Broglie relationship lambda = h/p makes wavelength inversely proportional to momentum.
Section 1 Question 15
Answer: 0 before and 0 after
The neutron and proton have lepton number zero. The electron contributes +1 and the electron antineutrino -1, giving zero after decay.
Section 1 Question 16
Answer: 8
For bodies orbiting the same central mass, T^2 is proportional to r^3. Therefore T_B/T_A = 4^(3/2) = 8.
Section 1 Question 17
Answer: 1/16
At fixed power, current becomes one quarter. Since cable loss is I^2R, the loss becomes (1/4)^2 = 1/16 of its original value.
Section 1 Question 18
Answer: 9.0 x 10^10 J
One milligram is 1.0 x 10^-6 kg. E = mc^2 = (1.0 x 10^-6)(3.0 x 10^8)^2 = 9.0 x 10^10 J.
Section 1 Question 19
Answer: Star X has the higher surface temperature.
Wien's law lambda_max T = constant means a smaller peak wavelength corresponds to a larger absolute temperature.
Section 1 Question 20
Answer: They produce two photons travelling in different directions.
Two photons can share the energy and carry equal and opposite momentum; a single photon cannot conserve momentum for a stationary pair.
Section 2 Question 21
- The initial components are v_x = 28.0 cos 35.0 degrees = 22.9 m s^-1 and v_y = 28.0 sin 35.0 degrees = 16.1 m s^-1.
- Solving 0 = 2.00 + 16.1t - 4.90t^2 gives the positive flight time t = 3.40 s.
- Horizontal motion is uniform, so the range is x = 22.9 x 3.40 = 77.9 m.
Detailed marking criteria
Part a (1 mark)
Awards one mark for accurately establishing this question-specific point: The initial components are v_x = 28.0 cos 35.0 degrees = 22.9 m s^-1 and v_y = 28.0 sin 35.0 degrees = 16.1 m s^-1.
Part a (1 mark)
Awards one mark for accurately establishing this question-specific point: Solving 0 = 2.00 + 16.1t - 4.90t^2 gives the positive flight time t = 3.40 s.
Part a (1 mark)
Awards one mark for accurately establishing this question-specific point: Horizontal motion is uniform, so the range is x = 22.9 x 3.40 = 77.9 m.
Section 2 Question 22
- For a perpendicular conductor, F = BIL = (0.420)(3.50)(0.180).
- The force magnitude is 0.265 N to three significant figures.
- The conventional-current right-hand rule gives a force towards the north.
Detailed marking criteria
Part a (1 mark)
Awards one mark for accurately establishing this question-specific point: For a perpendicular conductor, F = BIL = (0.420)(3.50)(0.180).
Part a (1 mark)
Awards one mark for accurately establishing this question-specific point: The force magnitude is 0.265 N to three significant figures.
Part a (1 mark)
Awards one mark for accurately establishing this question-specific point: The conventional-current right-hand rule gives a force towards the north.
Section 2 Question 23
- The Lorentz factor is gamma = 1/sqrt(1 - 0.960^2) = 3.57.
- The laboratory lifetime is Delta t = gamma Delta t_0 = 3.57 x 2.20 microseconds = 7.86 microseconds.
- The mean relativistic distance is d = v Delta t = (0.960)(3.00 x 10^8)(7.86 x 10^-6) = 2.26 x 10^3 m.
- Using the undilated lifetime would predict only 634 m, so the time-dilated laboratory lifetime gives a substantially longer survival distance.
- The increased ground-level muon count is evidence consistent with time dilation rather than a change in the muon's proper lifetime.
Detailed marking criteria
Part a (1 mark)
Awards one mark for accurately establishing this question-specific point: The Lorentz factor is gamma = 1/sqrt(1 - 0.960^2) = 3.57.
Part a (1 mark)
Awards one mark for accurately establishing this question-specific point: The laboratory lifetime is Delta t = gamma Delta t_0 = 3.57 x 2.20 microseconds = 7.86 microseconds.
Part b (1 mark)
Awards one mark for accurately establishing this question-specific point: The mean relativistic distance is d = v Delta t = (0.960)(3.00 x 10^8)(7.86 x 10^-6) = 2.26 x 10^3 m.
Part b (1 mark)
Awards one mark for accurately establishing this question-specific point: Using the undilated lifetime would predict only 634 m, so the time-dilated laboratory lifetime gives a substantially longer survival distance.
Part b (1 mark)
Awards one mark for accurately establishing this question-specific point: The increased ground-level muon count is evidence consistent with time dilation rather than a change in the muon's proper lifetime.
Section 2 Question 24
- Using widely separated points gives gradient approximately (1.54 - 0.30)/(3.0 x 10^14) = 4.13 x 10^-15 V s.
- The photoelectric equation gives gradient h/e, so h = e x gradient.
- h = (1.602 x 10^-19)(4.13 x 10^-15) = 6.62 x 10^-34 J s.
- Extrapolating V_s = 0 gives a threshold frequency of approximately 5.27 x 10^14 Hz.
- The work function is phi = hf_0 = (6.62 x 10^-34)(5.27 x 10^14) = 3.49 x 10^-19 J.
- This work function is approximately 2.18 eV.
- The non-zero threshold shows that emission depends on a minimum energy per photon, not only total beam intensity.
- The linear trend follows eV_s = hf - phi and its physically plausible Planck-constant gradient strengthens the photon interpretation.
- The estimate is limited by measurement scatter, surface contamination or uncertainty in extrapolating beyond the measured frequency range.
Detailed marking criteria
Part a (1 mark)
Awards one mark for accurately establishing this question-specific point: Using widely separated points gives gradient approximately (1.54 - 0.30)/(3.0 x 10^14) = 4.13 x 10^-15 V s.
Part a (1 mark)
Awards one mark for accurately establishing this question-specific point: The photoelectric equation gives gradient h/e, so h = e x gradient.
Part a (1 mark)
Awards one mark for accurately establishing this question-specific point: h = (1.602 x 10^-19)(4.13 x 10^-15) = 6.62 x 10^-34 J s.
Part b (1 mark)
Awards one mark for accurately establishing this question-specific point: Extrapolating V_s = 0 gives a threshold frequency of approximately 5.27 x 10^14 Hz.
Part b (1 mark)
Awards one mark for accurately establishing this question-specific point: The work function is phi = hf_0 = (6.62 x 10^-34)(5.27 x 10^14) = 3.49 x 10^-19 J.
Part b (1 mark)
Awards one mark for accurately establishing this question-specific point: This work function is approximately 2.18 eV.
Part c (1 mark)
Awards one mark for accurately establishing this question-specific point: The non-zero threshold shows that emission depends on a minimum energy per photon, not only total beam intensity.
Part c (1 mark)
Awards one mark for accurately establishing this question-specific point: The linear trend follows eV_s = hf - phi and its physically plausible Planck-constant gradient strengthens the photon interpretation.
Part c (1 mark)
Awards one mark for accurately establishing this question-specific point: The estimate is limited by measurement scatter, surface contamination or uncertainty in extrapolating beyond the measured frequency range.
Section 2 Question 25
- The neutron has valence composition udd and the proton uud.
- One down quark changes into an up quark.
- The other two quarks act as spectators in the stated valence model.
- Charge is conserved: 0 = +1 + (-1) + 0.
- Baryon number is conserved: the neutron and proton each have baryon number +1, while both leptons have 0.
- Lepton number is conserved: 0 = (+1 for e-) + (-1 for anti-nu_e).
- The antineutrino is required alongside the electron for lepton-number, energy and momentum accounting.
- At the first vertex, a down quark becomes an up quark and emits a virtual W- boson.
- The W- carries electric charge -1, so charge is conserved at the quark vertex.
- The virtual W- produces an electron and an electron antineutrino at the second vertex.
- The process is a weak interaction; the presence of a W boson distinguishes it from electromagnetic photon exchange.
Detailed marking criteria
Part a (1 mark)
Awards one mark for accurately establishing this question-specific point: The neutron has valence composition udd and the proton uud.
Part a (1 mark)
Awards one mark for accurately establishing this question-specific point: One down quark changes into an up quark.
Part a (1 mark)
Awards one mark for accurately establishing this question-specific point: The other two quarks act as spectators in the stated valence model.
Part b (1 mark)
Awards one mark for accurately establishing this question-specific point: Charge is conserved: 0 = +1 + (-1) + 0.
Part b (1 mark)
Awards one mark for accurately establishing this question-specific point: Baryon number is conserved: the neutron and proton each have baryon number +1, while both leptons have 0.
Part b (1 mark)
Awards one mark for accurately establishing this question-specific point: Lepton number is conserved: 0 = (+1 for e-) + (-1 for anti-nu_e).
Part b (1 mark)
Awards one mark for accurately establishing this question-specific point: The antineutrino is required alongside the electron for lepton-number, energy and momentum accounting.
Part c (1 mark)
Awards one mark for accurately establishing this question-specific point: At the first vertex, a down quark becomes an up quark and emits a virtual W- boson.
Part c (1 mark)
Awards one mark for accurately establishing this question-specific point: The W- carries electric charge -1, so charge is conserved at the quark vertex.
Part c (1 mark)
Awards one mark for accurately establishing this question-specific point: The virtual W- produces an electron and an electron antineutrino at the second vertex.
Part c (1 mark)
Awards one mark for accurately establishing this question-specific point: The process is a weak interaction; the presence of a W boson distinguishes it from electromagnetic photon exchange.
Diagnostic Checklist
| Topic | Questions | Marks | Marks Lost | Action |
|---|---|---|---|---|
| Unit 3 Topic 1 - Gravity and motion | Q1, Q6, Q11, Q16, Q21 | 7 | ___ | Review vectors, projectiles, circular motion, gravitation, satellites and Kepler's laws. |
| Unit 3 Topic 2 - Electromagnetism | Q2, Q7, Q12, Q17, Q22 | 7 | ___ | Review electric and magnetic fields, forces, induction, generators, transformers and electromagnetic radiation. |
| Unit 4 Topic 1 - Special relativity | Q3, Q8, Q13, Q18, Q23 | 9 | ___ | Review frames, simultaneity, time dilation, length contraction, momentum and mass-energy equivalence. |
| Unit 4 Topic 2 - Quantum theory | Q4, Q9, Q14, Q19, Q24 | 13 | ___ | Review interference, black-body radiation, photons, atomic spectra and matter waves. |
| Unit 4 Topic 3 - The Standard Model | Q5, Q10, Q15, Q20, Q25 | 15 | ___ | Review particle families, quark structure, gauge bosons, conservation laws and interaction diagrams. |