9702 · 1.3
Errors and Uncertainties in Paper 5 flashcards
Revision flashcards for Cambridge 9702 Errors and Uncertainties in Paper 5 (syllabus 1.3). Flip, recall, then mark a real past-paper question.
Card
Systematic error?
Consistent, repeatable error in the same direction — affects accuracy, not fixed by averaging.
Card
Random error?
Unpredictable scatter between readings — affects precision; reduced by repeating and averaging.
Card
Accuracy vs precision?
Accuracy = closeness to true value; precision = closeness of repeated readings to each other.
Card
Adding absolute uncertainties?
When adding or subtracting quantities, add absolute uncertainties: $\Delta z = \Delta x + \Delta y$.
Card
Multiplying percentage uncertainties?
When multiplying/dividing, add fractional uncertainties: $\frac{\Delta z}{z} = \frac{\Delta x}{x} + \frac{\Delta y}{y}$.
Card
Uncertainty in gradient?
Gradient uncertainty = |gradient of best fit ? gradient of worst acceptable line|.
Card
Worst acceptable line (WAL)?
Steepest or shallowest straight line still passing through all error bars on the graph.
Card
Zero error example?
A voltmeter not zeroed — every reading shifted by the same amount (systematic).