Standard form & significant figures
Physical Quantities & Units - OCR A-Level Physics
- Standard formWriting a number as a × 10ⁿ where 1 ≤ a < 10 and n is an integer. writes a number as A x 10^n where $1 \leq$A < 10.
- Use standard form for very large or very small quantities in physics.
- The number of significant figuresThe number of meaningful digits in a measured value, indicating its precision. in a result should match the data given.
- If the question gives data to 3 s.f., your answer should be to 3 s.f. (or 2-3 s.f.).
- Intermediate calculations should keep extra figures to avoid rounding errors.
- Only round at the final step.
Common Mistake
MEDIUM
Wrong: Giving a final answer to 6 significant figures when the data was given to 2 s.f.
Right: Your answer cannot be more precise than the least precise piece of data. If data is 2 s.f., give your answer to 2 s.f.
Right: Your answer cannot be more precise than the least precise piece of data. If data is 2 s.f., give your answer to 2 s.f.