AQA paper 3: practical skills, data analysis and your option · A-Level Physics · Courselo

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AQA paper 3: practical skills, data analysis and your option

6 min readA-Level Physics

Paper 3 is 2 hours, 80 marks and 32% of the A-level, with no multiple choice. Section A (45 marks) tests practical skills and data analysis, built around the 12 required practicals and unfamiliar experiments. Section B (35 marks) is your option: Astrophysics, Medical physics, Engineering physics, Turning points in physics or Electronics. Section A rewards technique more than knowledge, so it is the most trainable 45 marks in the qualification. The target is 64/80: 36 in Section A and 28 in the option. The notional A* for Section A in June 2026 was 34/45.

Timing plan

Elapsed	Target
0–2 min	Skim. Find any graph to plot and any table to complete
67 min	Section A finished (about 1.4 min per mark, with 8–10 min for a plotted graph)
115 min	Option finished (about 1.4 min per mark)
120 min	Units, significant figures and flagged items checked

If your option is strong, doing Section B first is fine, but set a hard stop at 48 minutes. Section A graph work expands to fill any time you give it.

The 12 required practicals: what to plot

Almost every Section A question comes back to “what do I plot, and what does the gradient mean?”

#	Practical	Plot	Gradient or intercept
1	Stationary waves on a string	$f$ against $\frac{1}{l}$	Gradient $\frac{1}{2}\sqrt{T/\mu}$
2	Young’s slits; diffraction grating	$w$ against $D$ ; $\sin\theta$ against $n$	Gradient $\frac{\lambda}{s}$ ; gradient
3	$g$ by free fall from rest	$h$ against $t^2$	Gradient $\frac{g}{2}$
4	Young modulus of a wire	Stress against strain	Gradient of the linear region is $E$
5	Resistivity of a wire	$R$ against $L$	Gradient $\frac{\rho}{A}$
6	emf and internal resistance	$V$ against $I$	Intercept $\varepsilon$ , gradient $-r$
7	Mass–spring or pendulum	$T^2$ against $m$ or $l$	Gradient $\frac{4\pi^2}{k}$ or
8	Boyle’s and Charles’s laws	$p$ against $\frac{1}{V}$ ; $V$ against $\theta$
9	Capacitor discharge	$\ln V$ against $t$	Gradient $-\frac{1}{RC}$
10	Force on a current-carrying wire	$F$ against $I$	Gradient $Bl$
11	Search coil at an angle	Peak emf against $\cos\theta$	Line through the origin
12	Inverse-square law for gamma rays	$\frac{1}{\sqrt{C - C_0}}$ against

For an unfamiliar equation, rearrange it into $y = mx + c$ and match terms. For a power law $y = kx^n$ , plot $\lg y$ against : the gradient is and the intercept is .

Section A: the rules that earn the marks

Tables. Each column heading gives the quantity and unit, such as “ $t$ / s”. Record raw readings to the instrument’s resolution with consistent decimal places. Give derived values to the same number of significant figures as the raw data, or one more.

Graphs.

Label axes with quantity and unit, and choose scales that use at least half the grid in each direction. Avoid scales in 3s or 7s.
Plot points to within half a small square, as neat crosses in sharp pencil.
Draw one smooth best-fit line or curve, with points balanced either side. Don’t join the dots.
Draw the gradient triangle over at least half the line, and read its corners from the line, not from data points.

Uncertainties.

A single reading, such as a thermometer: ± half the smallest division. A measurement from two readings, such as a length on a ruler: ± one division. Repeated readings: ± half the range.
Percentage uncertainty = $\frac{\text{uncertainty}}{\text{value}} \times 100\%$ . Add absolute uncertainties when adding or subtracting quantities. Add percentage uncertainties when multiplying or dividing. Multiply by $n$ for a power .

Method and evaluation. Name the independent, dependent and control variables. Credit specific techniques, not “be more careful”: a fiducial marker at the equilibrium position, timing many oscillations, a micrometer reading taken at several points and angles along a wire, reading scales at eye level to avoid parallax, checking for zero error, and data loggers for fast changes. Separate random errors (reduced by repeats and averaging) from systematic errors (zero errors, calibration; not reduced by repeats). Include one precise safety measure where relevant: tongs and distance for gamma sources, goggles for loaded wires.

Section B: preparing your option

Option	High-yield content
Astrophysics	Resolving and collecting power, CCDs; $m - M = 5\lg\frac{d}{10}$ ; Wien’s and Stefan’s laws; spectral classes and the HR diagram; ; and Hubble’s law; exoplanet detection

Treat the option as a full topic: it is worth more than a whole MCQ section. Learn its equations from the option section of the data booklet, practise its longer explanations (evidence for the expanding universe, how a gamma camera works, the Michelson–Morley null result) and time yourself at 1.4 minutes per mark.

Common mistakes

Quick recap

80 marks in 120 minutes: Section A done by 67 minutes, the option by 115.
Target 36/45 and 28/35.
For every required practical, know what to plot and what the gradient and intercept mean.
Graph marks: labelled axes, half-grid scales, accurate points, a best-fit line and a large triangle read from the line.
Uncertainties: half a division, one division or half the range, then add percentages and multiply by powers.

n

R_{s} = \frac{2 G M}{c^{2}}

R_s = \frac{2GM}{c^2}