This is a full practical question in the style of 9702 Paper 3. Work at the bench: read the scale through the magnifier, time the oscillations yourself, and fill in the answer sheet as you go. Then plot your own results on the graph paper and submit for marking. Every attempt uses a different strip, so the answers are always yours. Allow about an hour.
Checked: Cambridge 9702 Paper 3, 2017 to 2019 and 2023 to 2025. Only the papers in our collection are listed, so the real number may be higher. Question papers are available from Cambridge.
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The length and the first value of d are read to the nearest millimetre. The period comes from repeated timings of several oscillations, read from the stopwatch.
Six sets of readings over a wide range, headings with units, raw readings recorded consistently, calculated values correct and to sensible significant figures, and periods close to the true values.
Axes and scales, plotting, the line of best fit, a large gradient triangle and the y-intercept, marked exactly as in the graph trainer.
P and Q taken from your own gradient and intercept with the right units, then used to calculate L.
The marking follows the conventions in published Cambridge mark schemes. The experiments, readings and wording on this page are our own.