Measurements and Their Errors | AQA A-Level Physics (7408)
Measurements and Their Errors
- 87 questions
- 3 subtopics
- Paper 1, and available on Paper 3
- Paper 1 and Paper 3
Measurements and their errors runs through the whole course and can be examined on any paper.
It covers the SI system, how uncertainty is calculated and combined, and how to estimate a quantity to the right order of magnitude.
Sample questions from Measurements and Their Errors
Answer each one closed book first, then open the answer.
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Use of SI units and their prefixes
What power of ten does the SI prefix centi (c) represent?
Show the answer
10⁻². -
Use of SI units and their prefixes
What operation must be performed on an energy value in joules to express it in electronvolts?
Show the answer
Divide the energy in joules by 1.6 × 10⁻¹⁹. -
Limitation of physical measurements
State the formula for percentage uncertainty.
Show the answer
Percentage uncertainty = (Δx / x) × 100%, where Δx is the absolute uncertainty and x is the measured value. -
Limitation of physical measurements
What is a zero error?
Show the answer
A zero error is a type of systematic error where an instrument gives a non-zero reading when the true value is zero. -
Estimation of physical quantities
A value of 4 lies between 10⁰ and 10¹. Which order of magnitude is it closer to, and why?
Show the answer
It is closer to 10¹ (order of magnitude 1), because 4 exceeds the boundary value of approximately 3.16. -
Estimation of physical quantities
Why is knowledge of typical values for common physical quantities essential for making order-of-magnitude estimates?
Show the answer
Because estimation requires reasonable starting values for quantities such as masses, lengths, times, and speeds encountered in everyday and scientific contexts.
The 3 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Use of SI units and their prefixes | The base units, how derived units are built from them, and converting between prefixes. | 24 |
| Limitation of physical measurements | Random and systematic error, precision and accuracy, and combining absolute and percentage uncertainties. | 51 |
| Estimation of physical quantities | Working to an order of magnitude, and estimating a derived quantity from known values. | 12 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
AQA A-Level Physics Active Recall Guide
Every topic, not just this one. 3,682 questions with their answers.