Errors and uncertainties: past paper questions
Real questions on errors and uncertainties
The newest 20 of 197 written questions. Open one to see it on the real paper.
- 9702/22 · October/November 2025 · Q1c[2]
A quantity c relating to the motion of the balloon is calculated from three measured quantities k, F and v using the formula c = 2kF . v 2 The percentage uncertainties in the measured quantities are given in Table 1.2. Table 1.2 measured quantity percentage uncertainty k 5% F 3% v 4% The calculated value of c is 1.8. D...
See it on the paper → - 9702/42 · October/November 2025 · Q3b(ii)[2]
Before the measurement of Δh can be made, the glass bulb needs to reach thermal equilibrium with the environment for which the temperature is to be measured. State two disadvantages of using a constant volume gas thermometer to measure temperature.
See it on the paper → - 9702/42 · October/November 2025 · Q3b(iii)[1]
Suggest one situation in which a constant volume gas thermometer would be an appropriate type of thermometer to choose for measuring temperature.
See it on the paper → - 9702/42 · October/November 2025 · Q3b(iv)[3]
Level X aligns with 2.31 cm on the scale. At 0 °C, level Y aligns with 8.69 cm. At temperature θ, level Y aligns with 7.83 cm on the scale. Determine a value for θ in °C. θ = °C
See it on the paper → - 9702/53 · May/June 2025 · Q2c(iii)[2]
Determine the gradient of the line of best fit. Include the absolute uncertainty in your answer. gradient = 2.3 2.2 2.0 1 / 10 3 A –1 I 1.9 1.8 2.1 1.7 1.6 1.5 1.4 1.3 1.2 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 1 n
See it on the paper → - 9702/53 · May/June 2025 · Q2c(iv)[2]
Determine the y-intercept of the line of best fit. Include the absolute uncertainty in your answer. y-intercept =
See it on the paper → - 9702/53 · May/June 2025 · Q2d(i)[1]
R = Using your answers to (a), (c)(iii) and (c)(iv), determine the values of R and Z. Include appropriate units. (i)
See it on the paper → - 9702/53 · May/June 2025 · Q2d(ii)[1]
Determine the percentage uncertainty in your value of R. percentage uncertainty = %
See it on the paper → - 9702/53 · May/June 2025 · Q2e[1]
The experiment is repeated with 20 resistors, each of resistance R, connected in parallel between P and Q. Determine the total current I in the circuit. I = A
See it on the paper → - 9702/22 · February/March 2025 · Q1a[1]
Explain what is meant by the accuracy of a measured value.
See it on the paper → - 9702/41 · October/November 2024 · Q2b(i)[3]
State three conclusions that may be drawn from Fig. 2.1. The conclusions may be qualitative or quantitative.
See it on the paper → - 9702/52 · October/November 2024 · Q1[6]
Fig. 1.1 shows a coil made from resistance wire. Fig. 1.1 A potential difference V is applied to the coil. The temperature of the oil increases by Δθ in time t. It is suggested that Δθ is related to L by the relationship AtV 2 = mKΔθ + Z L where A is the cross-sectional area of the wire, and K and Z are constants. Plan...
See it on the paper → - 9702/52 · October/November 2024 · Q2a[1]
A graph is plotted of d 2 on the y-axis against 1 on the x-axis. sin 2 θ Determine expressions for the gradient and y-intercept. gradient =
See it on the paper → - 9702/52 · October/November 2024 · Q2b[2]
and d are given in Table 2.1. sin 2 θ Table 2.1 d / cm 28.5 4.39 24.8 ± 0.2 33.5 3.28 21.4 ± 0.2 42.5 2.19 17.1 ± 0.2 50.0 1.70 14.7 ± 0.2 57.5 1.41 12.9 ± 0.2 63.5 1.25 11.8 ± 0.2 d 2 / cm 2 Calculate and record values of d 2 / cm 2 in Table 2.1. Include the absolute uncertainties in d 2 . 1 sin 2 θ θ / ° (b) Values o...
See it on the paper → - 9702/52 · October/November 2024 · Q2c(i)[2]
Plot a graph of d 2 / cm 2 against 1 . Include error bars for d 2 . sin 2 θ
See it on the paper → - 9702/52 · October/November 2024 · Q2c(ii)[2]
Draw the straight line of best fit and a worst acceptable straight line on your graph. Label both lines.
See it on the paper → - 9702/52 · October/November 2024 · Q2c(iii)[2]
Determine the gradient of the line of best fit. Include the absolute uncertainty in your answer. gradient = 650 600 d 2 / cm 2 500 450 400 550 350 300 250 200 150 100 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 1 sin 2 θ
See it on the paper → - 9702/52 · October/November 2024 · Q2c(iv)[2]
y-intercept = Determine the y-intercept of the line of best fit. Include the absolute uncertainty in your answer. (iv)
See it on the paper → - 9702/52 · October/November 2024 · Q2d(ii)[1]
Determine the percentage uncertainty in n. percentage uncertainty in n = %
See it on the paper → - 9702/53 · October/November 2024 · Q2b[2]
Values of R and I are given in Table 2.1. Table 2.1 I / μA 1.50 194 ± 2 1.75 180 ± 2 1.92 172 ± 2 2.22 160 ± 2 2.48 150 ± 2 2.72 144 ± 2 1 –1 / A I R / kΩ 1 Calculate and record values of / A –1 in Table 2.1. I 1 Include the absolute uncertainties in .
See it on the paper →
What examiners said
The vast majority of candidates gave an acceptable explanation of accuracy. A small number of candidates inappropriately explained what was meant by the precision of a set of measured values. Very weak candidates sometimes thought that the accuracy was indicated by the number of significant figures or the number decimal places in the measured value.
— Examiner report, February/March 2025, 9702/22 Q1(a) (Cambridge)
The majority of the candidates correctly calculated the required percentage uncertainties. A small number of candidates inappropriately doubled the percentage uncertainty in the diameter.
— Examiner report, October/November 2023, 9702/23 Q1(b)(i) (Cambridge)
This question was usually answered correctly. A small minority of the candidates did not double the percentage uncertainty in the diameter.
— Examiner report, October/November 2023, 9702/23 Q1(b)(iii) (Cambridge)
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