plumiCapacitor charging and discharging: OCR A‑Level Physics B questions
OCR A-Level Physics B past-paper questions on 5.1.1.2 Capacitor charging and discharging, 2016–2025, with mark schemes and examiner’s reports where available.
Paper
All papers
Exam
All years
Calculations
Q32(b)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFLoading the question…
Open the full PDFYour answerLoading the question…
Open the full PDFYour answerLoading the question…
Open the full PDFYour answerQ3(a)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFQ3(b)(i)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFQ3(b)(ii)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFQ3(b)(iii)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFQ3(c)(i)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFQ3(c)(ii)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFLoading the question…
Open the full PDFYour answerLoading the question…
Open the full PDFYour answerQ34(b)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFLoading the question…
Open the full PDFYour answerQ2(a)(i)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFQ2(a)(ii)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFQ2(b)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFQ1(a)(i)
The whole paper ↗
Loading the start of the question…
Loading the question…
Open the full PDFQ1(a)(ii)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDFQ1(b)(i)
The whole paper ↗Loading the start of the question…
Loading the question…
Open the full PDF
All 34 questions on Capacitor charging and discharging, as a list
- June 2025, Paper 1, Q32(b) (4 marks): A 680 μF capacitor is charged until it stores 12 mJ energy. It is then discharged through a 1.2 kΩ resistor. Calculate the time taken for the capacitor to trans
- June 2024, Paper 1, Q30 (1 mark): The capacitor in this circuit is initially uncharged. A V The graphs all show the variation of different quantities associated with the circuit after the switch
- June 2023, Paper 1, Q23 (1 mark): A 220 μF capacitor discharges through a resistor R. The p.d. across the capacitor falls to 20% of its original value after 5 seconds. What is the value of resis
- June 2023, Paper 1, Q24 (1 mark): A 4700 μF capacitor is connected across a 6.0 V supply as shown. It is discharged through a 6.0 kΩ resistor. 6.0 V 4700 μF 6.0 kΩ How long does it take, after t
- June 2023, Paper 3, Q3(a) (4 marks): You are provided with the following apparatus: variable power supply (0 – 12 V) capacitor of unknown capacitance resistor of value 4.7 kΩ multimeter leads and s
- June 2023, Paper 3, Q3(b)(i) (3 marks): Capacitor discharge is an example of exponential decay and follows the equation –t V = V0e RC. Complete the ln V column in Table 3 and then perform a mathematic
- June 2023, Paper 3, Q3(b)(ii) (1 mark): Show that the value of the time constant, τ is approximately 25 s. [1]
- June 2023, Paper 3, Q3(b)(iii) (1 mark): Calculate the value of the capacitance. Capacitance = F [1]
- June 2023, Paper 3, Q3(c)(i) (3 marks): Starting from the equation given in (b)(i) and repeated below show that when t = 5τ, the energy stored in the capacitor, E = 4.5 × 10–5 E0, where E0 is the ener
- June 2023, Paper 3, Q3(c)(ii) (1 mark): Justify why this rule of thumb is useful to engineers. [1]
- June 2022, Paper 1, Q27 (1 mark): The capacitor in the circuit shown is initially uncharged. At time t = 0 s, the switch is moved to position X. What is the potential difference across the capac
- June 2022, Paper 1, Q28 (1 mark): When the capacitor is fully charged, the switch is moved to position Y. What is the energy stored on the capacitor after 10 s of discharge? A 0.013 J B 0.023 J
- June 2022, Paper 1, Q34(b) (3 marks): A simplified circuit is shown in Fig. 34.2. C R Fig. 34.2 Explain how the equation ∆Q ∆t = – Q RC can be used to find the charge remaining on the capacitor afte
- November 2021, Paper 1, Q16 (1 mark): A charged capacitor discharges through a resistor with the time constant τ = RC. What is the best explanation of the time constant τ? A τ is the time for the ch
- November 2021, Paper 2, Q2(a)(i) (2 marks): The operating range of the component is 5.2 V to 9.0 V. Show that 3.5 s after the switch is opened the p.d. across the component will be about 5.3 V. [2]
- November 2021, Paper 2, Q2(a)(ii) (3 marks): Estimate the average power delivered to the component during this time. Explain why the value is an average. average power = W Explanation: [3] 5 In recent year
- November 2021, Paper 2, Q2(b) (4 marks): A 120 F supercapacitor has an internal resistance of 30 mΩ. At time t = 0.0 s it stores 300 J. Calculate the minimum time taken for the capacitor to transfer 25
- November 2020, Paper 2, Q1(a)(i) (1 mark): Suggest why the student chooses to use a data logger rather than a digital meter. [1]
- November 2020, Paper 2, Q1(a)(ii) (3 marks): Use data from the graph to show that the capacitance of C is about 500 μF. [3]
- November 2020, Paper 2, Q1(b)(i) (3 marks): When the capacitor is charged to 4.2 V, the student resets the data logger to t = 0.0 s and moves the switch from position A to position B. Draw a line on Fig.
- November 2020, Paper 2, Q1(b)(ii) (3 marks): Calculate the time from the beginning of the discharge for the energy stored on the capacitor to fall to half its value. time = s [3]
- June 2019, Paper 1, Q39(a)(i) (2 marks): Use the graph to find the initial current when the capacitor starts to charge. Make your method clear. initial current = A [2]
- June 2019, Paper 1, Q39(a)(ii) (2 marks): Calculate the size of the electrical resistance in the charging circuit. resistance = Ω [2]
- June 2019, Paper 1, Q39(b) (1 mark): Explain why the charging current decreases as the capacitor charges. [1]
- June 2019, Paper 1, Q39(c)(i) (2 marks): A student makes an iterative model for the charging of the capacitor in (a), using time intervals ∆t = 2.0 s. The start conditions and the situation at times t
- June 2019, Paper 1, Q39(c)(ii) (2 marks): Compare the model values for the charge Q on the capacitor at time t = 4.0 s with the experimental values from Fig. 39.1. Explain any differences and state how
- June 2018, Paper 1, Q13 (1 mark): Which set of values A to D above, most closely represents the situation immediately after the switch is closed? Your answer [1]
- June 2018, Paper 1, Q14 (1 mark): Which set of values A to D above, most closely represents the situation 3 seconds after the switch is closed? Your answer [1]
- June 2017, Paper 1, Q34(a) (2 marks): Complete the numerical values in the two blank cells in the table. [2]
- June 2017, Paper 1, Q34(b)(i) (2 marks): Explain the physics behind the approximation in the third column of the table Q . T . RC [2]
- June 2017, Paper 1, Q34(b)(ii) (2 marks): State the assumption made in using this approximation and explain how its effect can be made insignificant. [2]
- June 2017, Paper 2, Q2(b) (2 marks): A student changes the circuit as shown in Fig. 2.2 6.0 V 2.0 kΩ 4.7 kΩ 2200 μF Fig. 2.2 Show that the time constant of the circuit is about 15 s. [2]
- June 2017, Paper 2, Q2(c) (2 marks): The graph in Fig. 2.3 shows how the p.d. across the capacitor varies with time up to 5 RC. Add a line to the graph that shows how the p.d. across the 4.7 kΩ res
- June 2017, Paper 2, Q2(d) (4 marks): Calculate the time it takes from the start of the charging for the p.d across the capacitor to reach 5.0 V. time = s [4]
Questions, mark schemes and examiner’s reports are © OCR, from their published past papers. Plumi isn’t affiliated with any exam board. Want whole papers? OCR A-Level Physics B past papers.
The Plumi iPad app also offers exam-style questions with AI feedback on your handwritten working.