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CIE A-Level Physics 9702 Paper 3 Practice Paper (AS Advanced Practical Skills) – 40 marks, 2 hours, with answers and mark scheme
TutorZone original practice paper – CIE A-Level Physics 9702 Paper 3 (AS Advanced Practical Skills)
2 questions, 13 parts – 40 marks – 2 hours – calculator allowed
Paper comparison
| Paper | Time | Marks | Role |
|---|---|---|---|
| Paper 3 (AS advanced practical skills) | 2 hours | 40 | this paper |
| Paper 4 (A Level structured) | 2 hours | 100 | other A Level paper |
| Paper 5 (planning, analysis and evaluation) | 1 hour 15 minutes | 30 | other A Level paper |
| Paper 2 (AS structured) | 1 hour 15 minutes | 60 | AS paper |
Data and formulae
| Quantity | Value |
|---|---|
| Acceleration of free fall g | 9.81 m s-2 |
| Pi | 3.1416 |
| Resistivity of copper (reference) | 1.7 x 10-8 ohm m |
| Resistivity of constantan (reference) | 4.9 x 10-7 ohm m |
| Elementary charge e | 1.60 x 10-19 C |
| Speed of light c | 3.00 x 108 m s-1 |
Questions
Total: 40 marks · 2 h · calculator allowed
Q 1 · Simple pendulum: measuring g [20]
(a) State the independent variable, the dependent variable and two control variables in this experiment, and say how each is measured. [4]
(b) Write out the procedure and explain how the random error in the timing is reduced. [4]
(c) Draw the table headings for the readings, including l and the values T and T squared obtained from t, with units and consistent significant figures. [3]
(d) State which two quantities should be plotted to give a straight line, and give the axis labels. [3]
(e) Find the gradient of the graph, use it to calculate g, and give the unit. [4]
(f) State the main sources of uncertainty in g and estimate its percentage uncertainty. [2]
Q 2 · Resistivity of a wire: R against l [20]
(a) Draw the circuit and describe the measurements, explaining how R is obtained from the readings. [4]
(b) Complete the table of V, I and R for the five lengths, with units. [3]
(c) State which straight-line graph should be plotted and what its gradient represents. [3]
(d) Read the gradient from the graph and give its unit. [2]
(e) Calculate the cross-sectional area and the resistivity, with units. [4]
(f) Estimate the percentage uncertainty in the resistivity and list the contributions. [3]
(g) Suggest one systematic effect that would make the resistivity too high, and a way to reduce it. [1]
Answers and mark scheme
| Q | Part | Answer | Mark points | marks |
|---|---|---|---|---|
| 1 | (a) | Independent variable = length l, measured with a metre rule from the support to the centre of the bob, using five values from 0.200 m to 1.000 m; dependent variable = period T, from the time t for 20 complete oscillations divided by 20; control variables = mass of the bob and the angle of swing (less than 10 degrees), with the same thread and support throughout. | All three variables named with measuring instruments, 2 marks Centre of bob and five lengths stated, 1 mark Sensible controls (mass, small angle), 1 mark |
4 |
| 1 | (b) | Pull the bob aside to less than 10 degrees and release it from rest, time 20 complete oscillations with a stopwatch to give t, repeat twice and average, then T = t / 20; change the length and repeat for five lengths, always releasing from the same position. | Small angle and timing 20 oscillations, 2 marks Repeat and average, 1 mark Five lengths with same release point, 1 mark |
4 |
| 1 | (c) | Six columns: l / m, t1 / s, t2 / s, mean t / s, T / s and T squared / s squared; lengths to 3 decimal places (0.200), times to 2 decimal places (for example 17.94 s for 20 oscillations), and T and T squared to 3 significant figures. | All six columns with units, 2 marks Consistent significant figures, 1 mark |
3 |
| 1 | (d) | Plot T squared on the y-axis against l on the x-axis, because squaring T = 2 pi root(l/g) gives T squared = (4 pi squared / g) times l, so the graph of T squared against l is a straight line through the origin. | Plot T squared against l, 2 marks Quote the linear relation, 1 mark |
3 |
| 1 | (e) | Gradient = change in T squared / change in l = 4.025 s squared per metre; g = 4 pi squared / gradient = 9.81 m per second squared, about 0.0% from the accepted 9.81 m per second squared. | Correct gradient with unit, 2 marks Correct substitution g = 4 pi squared / gradient, 1 mark Comparison with accepted value, 1 mark |
4 |
| 1 | (f) | The length is read to about 1 mm in 0.200 m, which is 0.5%, and the gradient from the best-fit line is good to about 2%, so the percentage uncertainty in g is about 2 to 3%; the timing reaction and the line fitting dominate. | Two specific sources, 1 mark Percentage uncertainty 2 to 3% with combination, 1 mark |
2 |
| 2 | (a) | Connect the cell, switch, rheostat and ammeter in series with the wire, with the voltmeter in parallel across the wire; measure the diameter d at three places with a micrometer and average; for each length l read V and I, then R = V / I. | Correct circuit (ammeter in series, voltmeter in parallel), 2 marks Micrometer readings averaged, 1 mark R = V / I stated, 1 mark |
4 |
| 2 | (b) | The current is kept at 0.200 A; V rises from 0.32 V to 1.59 V (2 decimal places), giving R from 1.60 ohms to 7.95 ohms. | All five sets of readings, 2 marks Units and significant figures consistent, 1 mark |
3 |
| 2 | (c) | Plot R on the y-axis against l on the x-axis; from R = rho l / A the gradient equals rho / A, so the gradient multiplied by the cross-sectional area gives the resistivity. | R against l, 2 marks Gradient equals rho / A, 1 mark |
3 |
| 2 | (d) | Gradient = change in R / change in l = 7.92 ohm per metre, using two points on the line, for example (0.200 m, 1.60 ohm) and (1.000 m, 7.95 ohm). | Correct gradient, 1 mark Unit ohm per metre, 1 mark |
2 |
| 2 | (e) | A = pi d squared / 4 = pi times (0.280 times 10 to the minus 3) squared / 4 = 6.158e-08 m squared; rho = gradient times A = 7.92 times 6.158e-08 = 4.88e-07 ohm metre. | Area correct using the radius, 2 marks Correct substitution, 1 mark Unit ohm metre, 1 mark |
4 |
| 2 | (f) | The diameter contributes 0.01 mm in 0.280 mm, which is 3.6%; the area uncertainty is twice that, 7.1%; the gradient contributes about 0.4%, giving about 7.6% in rho. | Diameter and doubling for area, 2 marks Total percentage given, 1 mark |
3 |
| 2 | (g) | The current heats the wire so its resistance rises with temperature, making R and rho too high; use a smaller current or switch off between readings so the wire stays at room temperature. | Specific cause with a workable improvement, 1 mark | 1 |
Topic breakdown
| Question | Topic | Marks |
|---|---|---|
| 1 | Simple pendulum: measuring g | 20 |
| 2 | Resistivity of a wire: R against l | 20 |
Common lost marks
- Timing a single swing instead of 20 oscillations, which magnifies the timing error twenty times.
- Plotting T against l, which gives a curve; T must be squared before plotting against l.
- Measuring to the fixed point of the thread rather than the centre of the bob, a systematic shift of one to two centimetres.
- Substituting the diameter into pi d squared / 4 without halving it, which makes the area and the resistivity four times too large.
Frequently asked
What does Paper 3 test?
Paper 3 is the AS advanced practical skills paper: 2 hours, 40 marks, two questions. Question 1 is a mechanics experiment (a simple pendulum to find g in this paper) and question 2 is an electricity experiment (V and I readings to find the resistivity of a wire), and both require planning, recording, graph work, gradient calculation and error evaluation.
Can I sit it without having done the experiment myself?
Yes. Paper 3 tests experimental design and data handling rather than memory, but you must be fluent with timing 20 oscillations, plotting T squared against l, plotting R against l, reading a micrometer and combining percentage uncertainties.
Where are marks most often lost?
Missing units and significant figures, plotting T against l instead of T squared against l, using the diameter instead of the radius when finding the area, and writing only human error in the evaluation instead of a specific source.
This paper is written by TutorZone tutors from the public syllabus; all questions and data are original and not endorsed by CIE.
The answer booklet gives mark-scheme points for study use only; please credit the source when reusing.
