CIE Insider
Paper 5 — Examiner Checklist
Paper 5 Self-Assessment Checklist
Grounded in 15 series of CIE Examiner Reports (2021–2025). Use this after every practice paper — tick what you got right, chase down what you missed.
0
Ticked
15
Series
30
Marks
18
Key Errors
0/10
▾
Variables
✓
Independent variable: named using the symbol from the question, unit given, method of variation stated
15/15
✓
Dependent variable: named using the symbol from the question, unit given, instrument named
15/15
✓
Control variables: at least two named using symbols — written as "[variable] will be kept constant by [specific method]", never just "control"
15/15
Examiner
Never write "control [variable]". Always write "[variable] will be kept constant by [specific method]". The method is the mark.
Diagram
✓
Diagram shows a workable experiment with key measurements labelled
15/15
✓
If electrical: circuit symbols correct — voltmeter in parallel, ammeter in series, ohmmeter in separate circuit, oscilloscope in parallel, switch included
8/15 ▲
Measurement
✓
Instrument named, specific quantity stated, method described (e.g. "repeat in different directions, find mean")
15/15
✓
Instrument is appropriate for the scale of measurement (micrometer only if measurement is in mm range, not for large lengths)
15/15
Graph & Relationship
✓
Both axes stated explicitly with quantities and units — not just "y = mx + c"
15/15
✓
Contains "relationship is valid if", "straight line", AND correct statement about origin (through origin only if c = 0 after rearranging)
15/15
✓
Constant is the subject of an equation linking it to the gradient or intercept (not just "use the gradient to find K")
14/15
Safety & Additional Detail
✓
Safety: specific to this experiment — states hazard, precaution, and why it reduces risk. Not generic lab rules.
15/15
✓
Additional detail: specific to this experiment, not generic. Uncertainty reduction explained by method, not just stated.
15/15
0/18
▾
2(a) — Rearranging into y = mx + c
✓
Equation fully rearranged into y = mx + c form, simplified (e.g. A/uA → 1/u)
15/15
✓
Negative sign included if present in the y-intercept
15/15
✓
y, x, m and c are explicitly identified — examiners need to see the connection to the graph
15/15
2(b) — Results Table
✓
Calculated values: same number of significant figures as raw data, or one more
15/15
✓
Log/ln quantities: number of DECIMAL PLACES matches significant figures in original quantity (digit before decimal point not counted)
15/15
✓
Uncertainties: correct combining rule used — add absolutes for +/−, add percentages for ×/÷, multiply % by |n| for powers
15/15
✓
ln/lg uncertainty: max-min method used, NOT the percentage method
15/15
✓
Repeated readings: absolute uncertainty = (max − min) / 2, not the full range
15/15
Examiner
For log uncertainties: Δ(ln V) = ΔV/V. Do not apply the percentage method. The most common wrong answer comes from incorrectly assuming the percentage uncertainty in ln(V) equals the percentage uncertainty in V.
2(c)(i) — Plotting
✓
Points plotted within half a small square; plotted point diameter less than half a small square (no large blobs)
15/15
✓
Error bars on every plotted point — symmetrical about each point, correct length, clear end caps
15/15
✓
Scale: points fill more than half the grid in both directions; no awkward scales (e.g. 1:3, 1:7)
15/15
✓
Axis labels: both axes include quantity AND unit in format "velocity v / m s⁻¹"
15/15
2(c)(ii) — Lines
✓
Best-fit line: balanced about the data — roughly equal points above and below. Does NOT join the top point to the bottom point.
15/15
✓
Worst acceptable line: passes through ALL error bars (through the bar, not near the point). Steepest or shallowest possible. Both lines labelled.
15/15
2(c)(iii) — Gradient
✓
Triangle covers more than half the drawn line; coordinates chosen on grid lines, NOT plotted data points
15/15
✓
gradient = Δy / Δx (NOT Δx / Δy); unit stated as y-unit ÷ x-unit; powers of ten from axis labels included
15/15
✓
Gradient uncertainty: coordinates from WORST ACCEPTABLE LINE stated, its gradient calculated, uncertainty = |gradient(best) − gradient(worst)| shown
15/15
2(c)(iv) — y-Intercept
✓
y-intercept calculated via y = mx + c substitution — NOT read directly from a false origin
15/15
✓
Intercept uncertainty: use gradient of WORST ACCEPTABLE LINE to calculate its intercept. Show: Δc = |c(best) − c(worst)|
15/15
2(d) — Extracting Physical Constants
✓
Gradient and/or intercept substituted explicitly — NOT data values from the table
15/15
✓
Powers of ten from axis labels included in calculation; final answer has correct unit and correct power of ten
15/15
✓
ln vs lg distinguished correctly: 10^(intercept) for lg axes; e^(intercept) for ln axes
15/15
Reference
▾
1
Uncertainty: incorrect combining rules (absolute vs percentage, conversion between them)
15/15
2
Gradient: small triangle, or reading from data points not the line
15/15
3
Worst acceptable line: not passing through all error bars, or gradient not calculated from it
15/15
4
Best-fit line: joining top to bottom point, or not balanced about the data
15/15
5
Error bars: not symmetrical, incorrect length, or missing
15/15
6
Graph: false origin error on y-intercept, or incorrect assumption line passes through origin
15/15
7
Significant figures in calculated column: not matching raw data precision
15/15
8
Rearranging equation into straight-line form: algebra errors, wrong form, missing negative sign
15/15
9
Gradient/intercept: not used to extract physical constant (data substitution used instead)
15/15
10
Control of variables: "keep constant" without stating how, or just writing "control"
15/15
11
Measurement: vague instrument description, wrong instrument for scale of measurement
15/15
12
Planning: vague responses, textbook rules, not specific to this experiment
15/15
13
"Relationship is valid if" + "straight" language missing from graph confirmation
15/15
14
Gradient uncertainty: working not shown, coordinates from worst acceptable line not stated
15/15
15
Units and powers of ten: missing or wrong on final numerical answers
15/15
16
Practical experience: plans that could not work in a laboratory
15/15
17
How to extract constant from graph: constant not made the subject of the equation
14/15
18▲
Circuit diagrams: unworkable, components incorrectly placed — INTENSIFYING from 2023
8/15
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