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Measurement Uncertainty Flashcards: Absolute & Percentage Practice

Practice 42 measurement uncertainty prompts: absolute and percentage amounts, arithmetic handoffs, and mistake repairs under a stated classroom interval model.

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An uncertainty amount needs a meaning before it can enter arithmetic. These 42 measurement uncertainty flashcards practice a stated classroom linear interval model with original short calculations, operation choices, mixed-step handoffs, and mistake repairs.

Here, x ± Δx specifies permitted values from x − Δx to x + Δx. All combinations of distinct input values are allowed. This is an exercise model, not a probability distribution or evidence about actual apparatus. Addition, subtraction, and exact scaling use exact interval widths. Products, quotients, and powers use explicitly labeled first-order estimates from summed relative contributions; those estimates are not generally exact symmetric bounds. Positive nominal inputs and denominator intervals above zero keep these tasks within that limited scope.

You'll retrieve an interval from a nominal value and half-width; convert absolute amounts to percentages and selected percentages back to absolute amounts; choose the right representation for an operation; and carry a calculated difference into a later quotient or a product into a later sum. A few repairs target adding percentages before a sum, subtracting contributions in a quotient, failing to scale a width, and reading uncertainty from decimal digits. Exact product and quotient endpoints make the approximation boundary visible. A few conceptual cards distinguish standard uncertainties from interval half-widths and identify the need to check covariance assumptions. They do not teach a second computation syllabus.

The sequence introduces interval meaning and representations before dependent calculations, then interleaves conversions, arithmetic, handoffs, repairs, and model limits. Same-concept variants have at least three unrelated cards between them. Long-term spacing belongs to the review scheduler.

You should already be comfortable with percentages and ordinary arithmetic. This is an evergreen topic deck, not a complete physics course or an exam-aligned package. It excludes instrument-resolution estimates, half-range rules, correlation and reused-input calculations, logarithms, trigonometric propagation, zero nominal values, denominators that reach zero, full professional uncertainty budgets, and clinical or safety decisions. Mechanical reversals of worked results are omitted because the inputs are generally not determined by an answer. The one reporting task states its rounding convention explicitly.

The numerical setups, prompts, explanations, and sequence were independently authored and checked by interval endpoints, exact fraction or decimal arithmetic, and first-order mathematical expansions. The distinction between uncertainty models was checked against BIPM's uncertainty definition, NIST's basic definitions, and NIST's combination rules. AQA's mathematical requirements establish that these arithmetic operations are familiar learner tasks; this deck does not claim curriculum alignment.

AI tools assisted with drafting, sequencing, and the decorative cover. Every final front and back was manually read during author review; numerical answers also have an exact-arithmetic audit. The cover was inspected at full size and across intended small crops. No apparatus experiment, learner trial, or professional credential is claimed. The original wording, organization, metadata, and generated cover are shared under CC0 1.0 to the extent applicable rights exist. The underlying facts remain common knowledge; cited material retains its own rights.

This is independent, unofficial study practice, with no affiliation to or endorsement by BIPM, NIST, or AQA. No examination questions, mark schemes, curriculum text, source exercises, competitor cards, logos, or trade dress were copied or adapted. See the linked official AQA requirements for its own course scope.

Cartes de ce paquet

  1. Carte 1

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. A length is 6.40 ± 0.08 cm. What interval does this specify?

    Réponse

    6.32 to 6.48 cm.

    Subtract and add the supplied half-width: 6.40 − 0.08 and 6.40 + 0.08.

  2. Carte 2

    Question

    In the classroom interval model, how do you turn an absolute half-width Δx into a percentage for a positive nominal value x?

    Réponse

    100 × Δx / x percent.

    Use the same unit for Δx and x. The ratio Δx/x is the relative amount before multiplying by 100.

  3. Carte 3

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. For a difference a − b, which expression gives its exact absolute half-width?

    Réponse

    Δa + Δb.

    The largest difference pairs the upper value of a with the lower value of b; the smallest pairs the opposite endpoints.

  4. Carte 4

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. A quantity is multiplied by an exact positive factor k. What happens to its absolute half-width?

    Réponse

    Multiply it by k.

    Both endpoints scale by k.

  5. Carte 5

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. Use first-order summed relative contributions. For z = ab with positive a and b and small relative half-widths, what relative amount do you use for z?

    Réponse

    Δa/a + Δb/b, approximately.

    Multiplying the nominal product by this sum gives its first-order absolute amount. The omitted product ΔaΔb prevents this from being a general exact symmetric bound.

  6. Carte 6

    Question

    A measurement is printed as 17.2 s, with no uncertainty statement. Can its uncertainty be determined from those digits alone?

    Réponse

    No.

    The displayed digits do not specify an interval, a standard deviation, or a coverage probability. An uncertainty statement and its meaning are needed.

  7. Carte 7

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. Add 9.60 ± 0.06 mm and 3.40 ± 0.02 mm. What is the total’s exact absolute half-width?

    Réponse

    0.08 mm.

    Add the widths: 0.06 + 0.02. The nominal total is 13.00 mm.

  8. Carte 8

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. A nominal mass of 72 g has a 1.5% interval half-width. What is its absolute half-width?

    Réponse

    1.08 g.

    72 × 1.5/100 = 1.08. This converts the supplied percentage; it does not estimate an instrument’s uncertainty.

  9. Carte 9

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. A positive quantity has a 1.2% half-width. For its fourth power, what is the first-order percentage amount?

    Réponse

    Approximately 4.8%.

    Multiply 1.2% by the magnitude of the exact exponent: 4 × 1.2%. This is a linear estimate, not an exact power interval.

  10. Carte 10

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. A model length 9.60 ± 0.24 mm is divided by exactly 12. What is the result’s exact absolute half-width?

    Réponse

    0.020 mm.

    0.24/12 = 0.020. The nominal result is 0.80 mm; the exact divisor adds no uncertainty contribution.

  11. Carte 11

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. Subtract 12.10 ± 0.02 cm from 18.70 ± 0.03 cm. What is the difference’s exact absolute half-width?

    Réponse

    0.05 cm.

    0.03 + 0.02 = 0.05. The nominal difference is 6.60 cm; subtracting nominal values does not subtract the interval widths.

  12. Carte 12

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. Use first-order summed relative contributions. Multiply lengths 4.00 ± 0.04 cm and 9.00 ± 0.18 cm. What is the product’s approximate percentage amount?

    Réponse

    Approximately 3.0%.

    The contributions are 0.04/4.00 = 1.0% and 0.18/9.00 = 2.0%. Add them for the first-order product estimate.

  13. Carte 13

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. Use first-order summed relative contributions. Divide 84.0 ± 0.42 m by 7.00 ± 0.14 s. What is the quotient’s approximate absolute amount?

    Réponse

    Approximately 0.30 m/s.

    The nominal quotient is 12 m/s. Its relative amount is 0.42/84.0 + 0.14/7.00 = 0.025, so 12 × 0.025 = 0.30 m/s.

  14. Carte 14

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. A calculated force is 42.0 ± 0.21 N. What is its percentage half-width?

    Réponse

    0.50%.

    100 × 0.21/42.0 = 0.50. Use the calculated quantity’s own nominal value in the denominator.

  15. Carte 15

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. A positive length has a 0.75% half-width. What is the first-order percentage amount for its square?

    Réponse

    Approximately 1.50%.

    The exact exponent is 2, so multiply the relative amount by 2. Do not square the percentage.

  16. Carte 16

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. A permitted length interval runs from 9.90 to 10.10 cm. What is its absolute half-width?

    Réponse

    0.10 cm.

    Half the interval’s full width is (10.10 − 9.90)/2 = 0.10 cm. Its midpoint is 10.00 cm.

  17. Carte 17

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. Convert 0.875 ± 0.003 m to centimeters using the exact factor 100 cm per meter. What is the absolute half-width in centimeters?

    Réponse

    0.30 cm.

    100 × 0.003 m = 0.30 cm. Convert the width along with the nominal value, which becomes 87.5 cm.

  18. Carte 18

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. Two time values are 22.40 ± 0.08 s and 16.40 ± 0.04 s. What percentage half-width belongs to their positive difference before a later ratio?

    Réponse

    2.0%.

    The difference is 6.00 s with half-width 0.08 + 0.04 = 0.12 s. Then 100 × 0.12/6.00 = 2.0%.

  19. Carte 19

    Question

    A student says that writing 7.80 g establishes an interval half-width of 0.01 g. Is that conclusion supported by the notation alone?

    Réponse

    No.

    The final decimal place is not an uncertainty model. Ask for the supplied uncertainty and whether it is a bound, a standard uncertainty, or another stated quantity.

  20. Carte 20

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. Use first-order summed relative contributions. A calculated sum is S = 36.0 ± 0.18 cm. Multiply it by a distinct length 8.00 ± 0.04 cm. What is the area’s approximate absolute amount?

    Réponse

    Approximately 2.88 cm².

    The nominal area is 288 cm². The relative contributions are 0.18/36.0 = 0.005 and 0.04/8.00 = 0.005, so 288 × 0.010 = 2.88 cm².

  21. Carte 21

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. Use first-order summed relative contributions. For a quotient of positive quantities, the numerator’s contribution is 2% and the denominator’s is 3%. A student subtracts them. What approximate percentage should replace that step?

    Réponse

    Approximately 5%.

    The linear interval estimate adds the magnitudes of the relative contributions for a quotient: 2% + 3%.

  22. Carte 22

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. A is 80.0 ± 0.4 cm and B is 30.0 ± 0.3 cm. Which has the larger percentage half-width?

    Réponse

    B.

    A has 100 × 0.4/80.0 = 0.5%; B has 100 × 0.3/30.0 = 1.0%. A larger absolute amount need not be larger in percentage terms.

  23. Carte 23

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. A positive quantity has a 1.6% half-width. What is the first-order percentage amount for its square root?

    Réponse

    Approximately 0.8%.

    The exact exponent is 1/2. Multiply 1.6% by 1/2; do not take the square root of the percentage.

  24. Carte 24

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. Add masses 7.80 ± 0.03 g and 4.20 ± 0.05 g, then divide by exactly 4. What is the final exact absolute half-width?

    Réponse

    0.020 g.

    Add the widths first, then scale: (0.03 + 0.05)/4 = 0.020 g. The nominal final value is 3.00 g.

  25. Carte 25

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. A rectangle has sides 2.00 ± 0.02 cm and 3.00 ± 0.03 cm. What is its exact permitted area interval?

    Réponse

    5.8806 to 6.1206 cm².

    Both sides stay positive. Multiply the lower endpoints for the minimum: 1.98 × 2.97. Multiply the upper endpoints for the maximum: 2.02 × 3.03.

  26. Carte 26

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. A length 7.00 ± 0.07 m is multiplied by exactly 5. A student keeps 0.07 m as the result’s half-width. What should replace it?

    Réponse

    0.35 m.

    The exact factor scales both nominal value and half-width: 5 × 0.07 = 0.35 m. The nominal result is 35.00 m.

  27. Carte 27

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. Use first-order summed relative contributions. Evaluate q = (a − b)/t using a = 46.0 ± 0.12 cm, b = 34.0 ± 0.06 cm, and t = 3.00 ± 0.03 s. What is q’s approximate percentage amount?

    Réponse

    Approximately 2.5%.

    The difference is 12.0 cm with half-width 0.18 cm, giving 1.5%. Add the time’s 1.0% contribution for the later quotient.

  28. Carte 28

    Question

    A worksheet supplies ± amounts but never says whether they are interval half-widths or standard uncertainties. Can you choose addition of widths or root-sum-square from that notation alone?

    Réponse

    No.

    First identify what the amounts mean and how the inputs relate. Root-sum-square combines suitable standard-uncertainty contributions under its stated assumptions; it does not turn interval half-widths into standard deviations.

  29. Carte 29

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. Use first-order summed relative contributions. Two positive factors have percentage contributions of 1% and 4%. A student multiplies the percentages. What approximate percentage belongs to the product?

    Réponse

    Approximately 5%.

    Add the first-order relative contributions: 1% + 4%. Multiplying percentages does not give the linear interval estimate.

  30. Carte 30

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. A rectangle has sides 2.00 ± 0.02 cm and 3.00 ± 0.03 cm. Its first-order area estimate is 6.00 ± 0.12 cm². Does that symmetric interval contain every permitted area?

    Réponse

    No.

    The exact upper endpoint is 2.02 × 3.03 = 6.1206 cm², beyond 6.12 cm². The omitted cross term is 0.02 × 0.03 = 0.0006 cm².

  31. Carte 31

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. A positive quantity x has a 1.0% half-width. For x raised to the exact power −3, what is the first-order percentage amount?

    Réponse

    Approximately 3.0%.

    Use the magnitude of the exponent: 3 × 1.0% = 3.0%. The reciprocal power does not create a negative uncertainty.

  32. Carte 32

    Question

    In a classroom linear interval calculation, a computed force has nominal value 60 N and a first-order percentage amount of 2.4%. What approximate absolute amount corresponds to it?

    Réponse

    Approximately 1.44 N.

    60 × 2.4/100 = 1.44 N. Convert the final quantity’s percentage using its own nominal value.

  33. Carte 33

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. Add 40.0 ± 0.4 g and 60.0 ± 0.3 g. A student adds the input percentages and reports 1.5%. What percentage half-width should the sum have?

    Réponse

    0.70%.

    The sum is 100.0 g with absolute half-width 0.4 + 0.3 = 0.7 g. Convert after adding: 100 × 0.7/100.0 = 0.70%.

  34. Carte 34

    Question

    Before using a classroom first-order quotient estimate with denominator y ± Δy and positive y, what inequality keeps its entire denominator interval above zero?

    Réponse

    y > Δy.

    The lower endpoint y − Δy must be positive. A finite quotient interval cannot be assumed when the denominator interval reaches zero.

  35. Carte 35

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. A length 8.00 ± 0.08 m is divided by exactly 100. What is the result’s percentage half-width?

    Réponse

    1.0%.

    The result is 0.0800 ± 0.0008 m. Both quantities scale together, so 100 × 0.0008/0.0800 remains 1.0%.

  36. Carte 36

    Question

    In NIST’s standard-uncertainty model, what does a standard uncertainty represent?

    Réponse

    An estimated standard deviation.

    It is a different input quantity from a permitted-interval half-width. The same ± notation does not make the two interchangeable.

  37. Carte 37

    Question

    A classroom interval model specifies 11.0 ± 0.2 cm as permitted values, with no probability distribution. Does this justify a 95% coverage claim?

    Réponse

    No.

    A permitted interval in this exercise model does not assign probabilities. A coverage claim needs a justified probabilistic interpretation.

  38. Carte 38

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. Use first-order summed relative contributions. Form ab + c with a = 6.00 ± 0.06 cm, b = 5.00 ± 0.05 cm, and distinct c = 20.00 ± 0.10 cm². What is the final first-order absolute amount?

    Réponse

    Approximately 0.70 cm².

    The product’s nominal value is 30 cm² and its relative amount is 1% + 1% = 2%, giving 0.60 cm². For the later addition, add absolute amounts: 0.60 + 0.10 = 0.70 cm².

  39. Carte 39

    Question

    A classroom first-order interval calculation carries nominal value 13.846 cm and approximate absolute amount 0.274 cm. Report the amount to two significant figures and the nominal value to the same decimal place. What report follows?

    Réponse

    Approximately (13.85 ± 0.27) cm.

    0.274 rounds to 0.27 cm; its last place is hundredths. Round 13.846 to that place. This uses the supplied reporting convention, not a universal rule.

  40. Carte 40

    Question

    For combined standard uncertainty, can the covariance terms always be dropped just because there are two input measurements?

    Réponse

    No.

    Uncorrelated input estimates justify dropping the covariance contributions. Otherwise their effect must be checked; a count of inputs does not establish the relationship.

  41. Carte 41

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. For positive quantities a = 6.00 ± 0.06 and b = 2.00 ± 0.02, what is the exact interval for a/b? Give exact fractions.

    Réponse

    297/101 to 101/33.

    The minimum is 5.94/2.02 = 297/101; the maximum is 6.06/1.98 = 101/33. They are about 2.940594 and 3.060606, so the deviations from the nominal 3 are asymmetric.

  42. Carte 42

    Question

    Classroom linear interval model; all combinations of distinct input values are allowed. Subtract 98.0 ± 0.10 m from 100.0 ± 0.10 m. What is the difference’s exact percentage half-width?

    Réponse

    10%.

    The nominal difference is 2.0 m and its half-width is 0.20 m. Thus 100 × 0.20/2.0 = 10%; a small difference can have a large relative amount.

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Measurement Uncertainty Flashcards: Absolute & Percentage Practice

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