Capacitance: past paper questions
Real questions on capacitance
The newest 20 of 116 written questions. Open one to see it on the real paper.
- 9702/41 · October/November 2025 · Q6a[4]
Two parallel plate capacitors C 1 and C 2 are connected to a supply that has a potential difference (p.d.) V S . The capacitors may be connected in series or in parallel. The supply provides charge Q S and the plates of the two capacitors acquire charges Q 1 and Q 2 respectively. The p.d.s across the plates of the capa...
See it on the paper → - 9702/41 · October/November 2025 · Q6b(i)[2]
Calculate the p.d. across the capacitor. p.d. = V (i)
See it on the paper → - 9702/41 · October/November 2025 · Q6b(ii)[2]
Calculate the charge on the capacitor. charge = C (ii)
See it on the paper → - 9702/41 · October/November 2025 · Q6b(iii)[3]
The capacitor is now connected in parallel with a capacitor of capacitance 180 μF that is initially uncharged. Determine the total energy, in mJ, now stored in the two capacitors. energy = mJ
See it on the paper → - 9702/41 · May/June 2025 · Q6a(ii)[1]
State the purpose of capacitor C. (ii)
See it on the paper → - 9702/42 · May/June 2025 · Q7b(iii)[2]
the time constant τ of the circuit. τ = s
See it on the paper → - 9702/42 · May/June 2025 · Q7c[3]
Use Fig. 7.2, Fig. 7.3 and your answer in (a) to explain why the variation of Q with t is exponential in nature.
See it on the paper → - 9702/52 · May/June 2025 · Q2d(i)[1]
E = Data: A = (2.2 ± 0.2) mF Using your answers to (a), (c)(iii) and (c)(iv), determine the values of E and C. Include appropriate units. (d) (i)
See it on the paper → - 9702/52 · May/June 2025 · Q2d(ii)[1]
Determine the percentage uncertainty in your value of C. percentage uncertainty = %
See it on the paper → - 9702/52 · May/June 2025 · Q2e[1]
The experiment is repeated with 10 capacitors, each of capacitance C, connected in parallel between P and Q. Determine the maximum potential difference V between P and Q. V = V
See it on the paper → - 9702/41 · October/November 2024 · Q6c(i)[2]
Show that the capacitance of C is 570 μF.
See it on the paper → - 9702/42 · October/November 2024 · Q7a[2]
Define the capacitance of a parallel‑plate capacitor.
See it on the paper → - 9702/42 · October/November 2024 · Q7b(i)[2]
charge 0 0 V p.d. Q On Fig. 7.1, sketch the variation of charge with p.d. for capacitor X as the p.d. increases from 0 to V. (i)
See it on the paper → - 9702/42 · October/November 2024 · Q7b(ii)[2]
Determine an expression, in terms of Q and V, for the work W done on capacitor X during the charging process. Explain your reasoning. W =
See it on the paper → - 9702/42 · October/November 2024 · Q7c(i)[3]
Complete Table 7.1 to show expressions, in terms of Q and V, for the final p.d.s across, and the final charges on, the two capacitors. Use the space below for any working that you need. Table 7.1 X Y final p.d. final charge
See it on the paper → - 9702/42 · October/November 2024 · Q7c(ii)[1]
State whether the total energy stored in the two capacitors is less than, the same as, or greater than the energy initially stored in capacitor X.
See it on the paper → - 9702/42 · May/June 2024 · Q6a[3]
Two capacitors X and Y are connected in series to a power supply of voltage V, as shown in Fig. 6.1. V Y Fig. 6.1 The capacitance of X is C X and the capacitance of Y is C Y . Derive an expression, in terms of C X and C Y , for the combined capacitance C T of the capacitors in this circuit. Explain your reasoning. X 6
See it on the paper → - 9702/42 · May/June 2024 · Q6b(i)[2]
Show that the supply voltage V is 5.0 V. ,
See it on the paper → - 9702/42 · May/June 2024 · Q6b(ii)[3]
Calculate the total energy, in mJ, stored in the capacitors when C Q has its maximum value. total energy = mJ
See it on the paper → - 9702/42 · February/March 2024 · Q4a[2]
Three capacitors are connected as shown in Fig. 4.1. 10 μF 45 μF 20 μF Fig. 4.1 Determine the total capacitance, in μF, of the network of three capacitors. capacitance = μF
See it on the paper →
What examiners said
Candidates who were mathematically confident were able to work through the algebra and achieve credit. Candidates should use the white space on the question paper to rearrange the equation into an equation of a straight line.
— Examiner report, October/November 2023, 9702/52 Q2(a) (Cambridge)
There were some errors in values of ln (V / V) caused by incorrect rounding. Many candidates did not allow correctly for the number of significant figures in ln (V / V). Since V was recorded to three significant figures, values of ln (V / V) should have been recorded to three (or four) decimal places – the number before the decimal point in a logarithmic quantity is not included. A common error wa...
— Examiner report, October/November 2023, 9702/52 Q2(b) (Cambridge)
Many candidates were able to use the exponential formula to show the value of the time constant. Some used the total time elapsed (0.04 s) rather than the time interval (0.02 s). Some attempted to use τ = RC, but not enough information was known at this stage for this equation to be helpful.
— Examiner report, May/June 2023, 9702/41 Q5(b)(ii) (Cambridge)
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