9702 · 1.3
Errors and Uncertainties in Paper 5
Master errors and uncertainties for Cambridge A-Level Physics Paper 5. Learn to distinguish systematic and random errors, calculate uncertainties in derived quantities, and apply these skills to graphical analysis and experimental planning. Syllabus coverage: understand and explain the effects of systematic errors (including zero errors) and random errors in measurements understand the distinction between precision and accuracy assess the uncertainty in a derived quantity by simple addition of absolute or percentage uncertainties
Need to know
What you need to know
- **Systematic Errors:** These are consistent, repeatable errors that cause your measurements to be consistently off from the true value in the same direction. For example, a voltmeter that has not been zeroed correctly (a zero error) will give every reading as slightly too high or too low. Systematic errors affect the *accuracy* of your results. They cannot be reduced by repeating measurements and averaging.
- **Random Errors:** These are unpredictable variations in measurements. They can be caused by factors like fluctuations in environmental conditions, misreading a scale, or variations in reaction time. Random errors cause a scatter of readings around a mean value. They affect the *precision* of your results. The effect of random errors can be reduced by taking multiple readings and calculating an average.
Explanation
Errors and Uncertainties in Paper 5
- Distinguish between systematic and random errors and their effects on experimental data.
- Explain the difference between accuracy and precision.
- Calculate absolute and percentage uncertainties in derived quantities.
- Determine the uncertainty in the gradient and y-intercept of a line of best fit.