Capacitors: Edexcel International A Level Physics questions

Every Edexcel International A Level Physics exam question on Capacitors (specification points 100–104), 2019–2025, with its mark scheme and examiner’s report.

All 76 questions on Capacitors, as a list

June 2025, Unit 4, Q2 (1 mark): A capacitor is charging. A graph of potential difference against charge is shown. Potential difference 0 0 Charge Which of the following gives the capacitance o
June 2025, Unit 4, Q17(a) (1 mark): State the potential difference across the capacitor at the end of a period of discharge. (1) Potential difference =
June 2025, Unit 4, Q17(b)(i) (5 marks): Deduce whether the output with the capacitor shown on the graph is consistent with a resistor tolerance of ± 5%. (5)
June 2025, Unit 4, Q17(b)(ii) (3 marks): Calculate the change in the energy stored in the capacitor during the discharging process. (3) Change in the energy stored =
June 2025, Unit 4, Q17(b)(iii) (3 marks): The resistor is replaced by a bulb with a much lower resistance than 6.8 kΩ. Explain why the output is now very similar to the original output of the power supp
June 2025, Unit 6, Q1(a)(i) (2 marks): Describe two safety precautions the student should take when using electrolytic capacitors in a circuit. (2)
June 2025, Unit 6, Q1(a)(ii) (2 marks): The student moved the switch to position A to charge the 680 µF electrolytic capacitor. She moved the switch to position B to connect the capacitor to another c
June 2025, Unit 6, Q1(b) (3 marks): The student charged the 680 µF capacitor to different potential differences, V1. For each value of potential difference V1, she connected the 680 µF capacitor t
January 2025, Unit 4, Q10 (1 mark): A charged capacitor C1 stores energy W1. A charged capacitor C2 stores energy W2. C1 has half the capacitance of C2. C1 is charged to half the potential differe
January 2025, Unit 4, Q20(a)(i) (4 marks): Explain how the current in the circuit varies when the switch is connected to position X. You do not need to do any calculations. (4)
January 2025, Unit 4, Q20(a)(ii) (3 marks): Sketch a graph to show the variation of current in the circuit as the capacitor is charged. Include the maximum value of current in the circuit. (3)
January 2025, Unit 4, Q20(b)(i) (2 marks): Show that the time constant of the circuit is about 60 s. (2)
January 2025, Unit 4, Q20(b)(ii) (3 marks): The student connected the switch to position Y for a time of 3 minutes. Determine, using the time constant of the circuit, the percentage of the original potent
January 2025, Unit 4, Q20(c) (4 marks): After the capacitor was fully discharged, the student connected the switch back to position X to recharge the capacitor. The student used the voltage sensors to
January 2025, Unit 4, Q20(d) (2 marks): The student connected a second identical capacitor in series with the first capacitor. She connected the switch to position X to charge both capacitors. Explain
October 2024, Unit 4, Q14 (6 marks): *14 The diagram shows a circuit with a cell of potential difference (p.d.) V0 in series with a capacitor, a resistor and a switch. A voltmeter measures the pote
June 2024, Unit 4, Q6 (1 mark): A capacitor of capacitance C is charged to a potential difference of V0. The capacitor then discharges through a resistor of resistance R. After time t the pote
June 2024, Unit 4, Q12(a) (1 mark): Add to the diagram to show a suitable circuit for measuring the current as the capacitor charged. (1)
June 2024, Unit 4, Q12(b)(i) (3 marks): The resistance of the resistor is 5.1 kΩ. Show that the capacitance of the capacitor is about 0.02 F. (3)
June 2024, Unit 4, Q12(b)(ii) (3 marks): Calculate the charge on the capacitor when it is fully charged. (3) Charge =
June 2024, Unit 4, Q12(b)(iii) (2 marks): Calculate the energy stored by the capacitor when it is fully charged. (2) Energy =
June 2024, Unit 6, Q1(a) (2 marks): State two safety precautions the student should take when connecting and using the circuit. (2)
June 2024, Unit 6, Q1(c)(iii) (3 marks): Determine the efficiency of the electric motor. maximum potential difference across capacitor = 6 V capacitance of capacitor = 4700 μF m = 20 g (3) Efficiency =
January 2024, Unit 4, Q7 (1 mark): A potential difference V is connected across a capacitor of capacitance C. The charge stored on the capacitor is Q. V C The capacitor is replaced with two capac
January 2024, Unit 4, Q11 (3 marks): A student selects the capacitor shown to use in a circuit. (Source: © David J. Green – electrical/Alamy Stock Photo) The tolerance of the capacitor is ± 20%. Ca
January 2024, Unit 4, Q18(a)(i) (4 marks): Determine a value for the capacitance C of the capacitor. (4) C =
January 2024, Unit 4, Q18(a)(ii) (3 marks): Sketch on the axes below how current I in the circuit would vary with t. You should include the value of the maximum current. (3) I 0 t
January 2024, Unit 4, Q18(b) (3 marks): The student connected a second 168 kΩ resistor in parallel with the first resistor. Explain how the time taken to charge the capacitor would change. You do not
October 2023, Unit 4, Q9 (1 mark): A capacitor discharges through a resistor. The time constant of the circuit is 5 s. What is the time taken, in s, for the charge on the plates of the capacitor
October 2023, Unit 4, Q18(a) (4 marks): The capacitor is labelled as 470 µF, with a tolerance of ±10%. Evaluate whether the capacitance of the capacitor is within the stated tolerance. (4)
October 2023, Unit 4, Q18(b) (3 marks): An ultracapacitor is a high-capacity capacitor. One ultracapacitor has a capacitance of 47 F. The maximum charge this capacitor can store is 56 C. It is suggest
June 2023, Unit 4, Q2 (1 mark): There is a potential difference of 6 V across a 220 μF capacitor. Which of the following expressions gives the charge stored on the capacitor? A 0.5 × 2.2 × 10
June 2023, Unit 4, Q18(a) (4 marks): The value marked on the capacitor is 22 μF. Show that this value is correct. resistance of resistor = 240 kΩ (4)
June 2023, Unit 4, Q18(b)(ii) (2 marks): Calculate the time for which the spheres were in contact. resistance in circuit = 49 Ω potential difference across capacitor before collision = 6.18 V potential
January 2023, Unit 4, Q16(a) (2 marks): Give two reasons why the circuit did not operate as intended. (2)
January 2023, Unit 4, Q16(b)(i) (3 marks): Determine the resistance in the circuit when the switch was at position Y. (3) Resistance =
January 2023, Unit 4, Q16(b)(ii) (4 marks): Determine the average current in the circuit between t = 0 s and t = 30 s. (4) Average current =
January 2023, Unit 4, Q16(b)(iii) (3 marks): Calculate the energy dissipated by the current in the circuit between t = 0 s and t = 30 s. (3) Energy dissipated =
October 2022, Unit 4, Q5 (1 mark): The graph shows how the charge Q stored on the plates of a capacitor varies with the potential difference V across the plates. Q / nC 550 0 12 V / V Which of th
October 2022, Unit 4, Q12(a) (4 marks): When the capacitor is completely discharged, the two-way switch is moved to position S1 at time t = 0 s. Complete the graph to show how the current varies with
October 2022, Unit 4, Q12(b) (4 marks): The capacitor in the defibrillator discharges when the switch is moved to position S2 . The defibrillator is required to deliver a discharge current of at least
June 2022, Unit 4, Q3 (1 mark): When the potential difference across a capacitor is V, the energy stored by the capacitor is W. Which of the following gives the energy stored by the capacitor
June 2022, Unit 4, Q9 (1 mark): Which of the following units is equivalent to the farad? A C V −1 B J V −1 C Ω s −1 D s J −1
June 2022, Unit 4, Q15(a)(i) (2 marks): Sketch a graph to show how the potential difference VC across the capacitor varies with time t as the switch is closed. The time constant T for this circuit is
June 2022, Unit 4, Q15(a)(ii) (2 marks): Explain how the potential difference VR across the resistor varies with time after the switch is closed. (2)
June 2022, Unit 4, Q15(a)(iii) (2 marks): Show that VC is given by the equation t VC = 5 – 5e– RC where R is the resistance of the resistor and C is the capacitance of the capacitor. (2)
June 2022, Unit 4, Q15(b) (3 marks): The input to the integrated circuit should be 3.3 V at a time 3.5 seconds after the switch is closed. The following capacitors are available: 4.7 μF 10 μF 15 μF
January 2022, Unit 4, Q14(a) (2 marks): Determine whether the initial value of current on the graph is consistent with the values stated on the circuit diagram. (2)
January 2022, Unit 4, Q14(b) (2 marks): Explain how the current on ammeter A2 would vary over the same time interval. (2)
January 2022, Unit 4, Q14(c) (3 marks): Determine the capacitance of the capacitor. (3) Capacitance =
January 2022, Unit 4, Q14(d) (2 marks): Determine the charge stored on the capacitor after 30 s. (2) Charge stored on capacitor after 30 s =
January 2022, Unit 4, Q14(e) (2 marks): Determine the maximum energy stored by the capacitor. (2) Maximum energy =
October 2021, Unit 4, Q7 (1 mark): A battery of e.m.f. V is connected to a capacitor as shown. The capacitor is initially uncharged. V Work is done by the battery to transfer a charge Q from one
October 2021, Unit 4, Q14(a) (3 marks): Explain how this circuit can maintain power to the electronic controller if the switch is opened for a short time. (3)
October 2021, Unit 4, Q14(b) (2 marks): The switch is opened. Calculate the time taken for the potential difference across the capacitor to decrease to 4.0 V. Assume the resistance of the electronic c
October 2021, Unit 4, Q14(c) (4 marks): The switch is closed at time t = 0 and then opened at t = 20 s. Sketch a graph on the axes below to show how current I through the resistor varies with t. (4) I
June 2021, Unit 4, Q17(a) (3 marks): Add to the diagram to show a suitable circuit for charging and discharging the capacitor while measuring the p.d. across it. (3)
June 2021, Unit 4, Q17(b)(i) (2 marks): Sketch, on the same axes, a graph to show how the p.d. across the resistor varies with time. (2)
June 2021, Unit 4, Q17(b)(ii) (3 marks): Show that the p.d V across the capacitor when it is charging is given by V = V0 – V0e–t / RC where V0 is the e.m.f. of the battery t is the time R is the resis
June 2021, Unit 4, Q17(b)(iii) (4 marks): During the charging process, the student recorded the p.d. across the capacitor and the resistance of the resistor. The capacitors available had the following v
June 2021, Unit 4, Q17(b)(iv) (2 marks): Calculate the charge on the fully charged capacitor. (2) Charge =
June 2021, Unit 4, Q17(b)(v) (2 marks): Calculate the energy stored by the fully charged capacitor. (2) Energy stored =
January 2021, Unit 4, Q5 (1 mark): An uncharged capacitor, a resistor, a switch and a cell are connected in series as shown. C R Which of the following shows how the charge stored on the capacito
January 2021, Unit 4, Q10 (1 mark): A charged capacitor is connected across a resistor of resistance R and the current in the resistor is measured. A graph of ln (current) against time is plotted
January 2021, Unit 4, Q11(a) (2 marks): Calculate the total charge stored by the capacitors. (2) Total charge stored =
January 2021, Unit 4, Q11(b) (2 marks): Calculate the total energy stored by the capacitors. (2) Total energy stored =
January 2021, Unit 6, Q2(a) (3 marks): Draw an appropriate circuit diagram for this investigation. (3)
January 2021, Unit 6, Q2(b) (1 mark): State one safety precaution the student should take. (1)
January 2021, Unit 6, Q2(c) (6 marks): The student had a stopwatch. Describe how the student should determine an accurate value for the total capacitance of the capacitors. (6)
January 2021, Unit 6, Q2(d) (2 marks): The student repeated the investigation but used a data logger instead of a stopwatch and an ammeter. Suggest why using a data logger would improve this investig
October 2020, Unit 4, Q3 (1 mark): A potential difference (p.d.) V is connected across a capacitor of capacitance C. The charge stored on the capacitor is Q. V C The capacitor is replaced with tw
October 2020, Unit 4, Q4 (1 mark): The SI unit of capacitance is the farad. Which of the following gives the base units of the farad? A C V–1 B C2 J–1 C kg–1 m–2 A2 s4 D kg–1 m–2 s–2 C–2
October 2020, Unit 4, Q15(c) (5 marks): The student tested the capacitor by charging it until the p.d. across the capacitor was 600 V and recording the p.d. as it was discharged through a resistor of
January 2020, Unit 4, Q17(a) (4 marks): The diagram shows the student’s design. R 12 V C The student uses a light emitting diode (LED) and a resistor R. The LED stops emitting light when the potential
January 2020, Unit 4, Q17(b) (3 marks): In practice, the resistance of the LED does not stay constant. The graph shows how current varies with potential difference (p.d.) for the LED. current 0 1.4 V
January 2020, Unit 4, Q17(c) (3 marks): The student states: “A capacitor is being used in this circuit. The function of the capacitor is to store electric charge.” Explain why this is not a complete d

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