plumiElectromagnetism: OCR A‑Level Physics B questions
Every OCR A-Level Physics B exam question on 6.1.1 Electromagnetism, 2016–2025, with its mark scheme and examiner’s report.
Find questions1,881
Calculations
Q38(a)
The whole paper ↗
Q38(b)
The whole paper ↗
Q38(c)
The whole paper ↗
Q8(b)
The whole paper ↗
Q2(c)(ii)
The whole paper ↗![June 2025 Paper 3, question 2(c)(ii): Use the value of gradient to calculate the value of magnetic field strength. Magnetic field strength = T [3]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h55703-jun25-02-cii-qp.webp?v=3)
Q31(a)
The whole paper ↗![June 2024 Paper 1, question 31(a): Explain how an alternating current in the primary coil causes an alternating current in the secondary coil. [3]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h55701-jun24-31-a-qp.webp?v=3)
Q31(b)
The whole paper ↗
Q7(a)(i)
The whole paper ↗![June 2023 Paper 2, question 7(a)(i): Calculate the maximum flux linkage in the coil. maximum flux linkage = Wb turns [2]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h55702-jun23-07-ai-qp.webp?v=3)
Q7(a)(ii)
The whole paper ↗![June 2023 Paper 2, question 7(a)(ii): The coil has sides of length 12 cm. It has 400 turns. Calculate the flux density B of the magnetic field. flux density B = T [2]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h55702-jun23-07-aii-qp.webp?v=3)
Q7(b)
The whole paper ↗
Q4(a)(i)
The whole paper ↗![June 2023 Paper 3, question 4(a)(i): The coil has 10 turns of radius 0.020 m. The field strength is 5.0 mT. Show that the flux linkage of the coil is about 6.3 × 10–5 Wb. [2] The coil is rotated at](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h55703-jun23-04-ai-qp.webp?v=3)
![June 2023 Paper 3, question 4(a)(ii): Suggest and explain why the trace has the shape shown on Fig. 4.3. [2]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h55703-jun23-04-aii-qp.webp?v=3)
Q4(a)(iii)
The whole paper ↗
Q4(a)(iv)
The whole paper ↗
Q4(b)(i)
The whole paper ↗![June 2023 Paper 3, question 4(b)(i): Add to Fig. 4.5 a drawing of the trace produced by the 20-turn coil. [2] 16 The driving force spinning the coil is removed. Fig. 4.6 shows how the flux linkage](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h55703-jun23-04-bi-qp.webp?v=3)
Q4(b)(ii)
The whole paper ↗![June 2023 Paper 3, question 4(b)(ii): Using the graph in Fig. 4.6, estimate the emf induced in the coil at the instant the flux linkage is zero at 0.23 s. Show all your working. emf = V [3]](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/h55703-jun23-04-bii-qp.webp?v=3)
All 64 questions on Electromagnetism, as a list
- June 2025, Paper 1, Q22 (1 mark): The graph shows how the flux linkage for a coil rotating in a magnetic field varies with time. N Φ 0 t 0 Which graph shows how the induced e.m.f. ε in the coil
- June 2025, Paper 1, Q38(a) (5 marks): The filament lamp connected to the secondary coil is rated at 3 V, 0.6 W. In one experiment the number of turns on the primary coil is 400 and the number of tur
- June 2025, Paper 1, Q38(b) (3 marks): Fig. 38.2 shows an enlarged top view of the top section of the laminated core. Fig. 38.2 Iron (conductor) Iron oxide (insulator) Explain how the laminations mak
- June 2025, Paper 1, Q38(c) (3 marks): In practice the transformer is not ideal and the students find that the values of the potential difference across the primary coil and the current in it are sig
- June 2025, Paper 2, Q8(b) (2 marks): Fig. 8 shows how the flux through a coil of 170 turns in a dynamic microphone oscillating in a magnetic field changes with time. Fig. 8 1.25 / μWb 1.00 0.75 0.5
- June 2025, Paper 2, Q10 (6 marks): 10* Using appropriate equations, explain and compare how the phase of the output signal from dynamic and condenser microphones relates to the phase of the incid
- June 2025, Paper 3, Q2(c)(ii) (3 marks): Use the value of gradient to calculate the value of magnetic field strength. Magnetic field strength = T [3]
- June 2024, Paper 1, Q14 (1 mark): The diagram shows a circular coil with its plane parallel to a uniform magnetic field. R uniform P Q magnetic T field S The coil can move in three ways within t
- June 2024, Paper 1, Q31(a) (3 marks): Explain how an alternating current in the primary coil causes an alternating current in the secondary coil. [3]
- June 2024, Paper 1, Q31(b) (2 marks): The table shows the values of the resistor and of the potential differences in the coils. Primary Secondary Secondary potential Primary current potential Resist
- June 2023, Paper 1, Q7 (1 mark): Here are some data for an ideal transformer: number of turns on primary coil = 200 number of turns on secondary coil = 400 primary voltage = 18.0 V output power
- June 2023, Paper 2, Q7(a)(i) (2 marks): Calculate the maximum flux linkage in the coil. maximum flux linkage = Wb turns [2]
- June 2023, Paper 2, Q7(a)(ii) (2 marks): The coil has sides of length 12 cm. It has 400 turns. Calculate the flux density B of the magnetic field. flux density B = T [2]
- June 2023, Paper 2, Q7(b) (4 marks): Suggest and explain two modifications to the generator that would increase the e.m.f. induced without changing the frequency of the rotor. You may refer to equa
- June 2023, Paper 3, Q4(a)(i) (2 marks): The coil has 10 turns of radius 0.020 m. The field strength is 5.0 mT. Show that the flux linkage of the coil is about 6.3 × 10–5 Wb. [2] The coil is rotated at
- June 2023, Paper 3, Q4(a)(ii) (2 marks): Suggest and explain why the trace has the shape shown on Fig. 4.3. [2]
- June 2023, Paper 3, Q4(a)(iii) (3 marks): The horizontal divisions on the trace representing time are set at 0.625 s/div. Using the trace shown in Fig. 4.3, calculate the angular frequency, ω, of the co
- June 2023, Paper 3, Q4(a)(iv) (2 marks): The angle θ, that the normal to the plane of the coil makes with the field lines varies with time as the coil rotates. Angle θ is shown in Fig. 4.4. Fig. 4.4 θ
- June 2023, Paper 3, Q4(b)(i) (2 marks): Add to Fig. 4.5 a drawing of the trace produced by the 20-turn coil. [2] 16 The driving force spinning the coil is removed. Fig. 4.6 shows how the flux linkage
- June 2023, Paper 3, Q4(b)(ii) (3 marks): Using the graph in Fig. 4.6, estimate the emf induced in the coil at the instant the flux linkage is zero at 0.23 s. Show all your working. emf = V [3]
- June 2023, Paper 3, Q4(b)(iii) (6 marks): This question is about inducing an emf in a coil of wire. Fig. 4.1 shows a coil of wire perpendicular to a uniform magnetic field. Fig. 4.1 0.020 m 0.020 m (iii
- June 2022, Paper 1, Q29 (1 mark): Here are some data about an ideal transformer: input power: 36 W primary current: 4.8 A number of turns on primary coil: 2000 secondary voltage: 60 V What is th
- June 2022, Paper 2, Q2(a)(i) (4 marks): The core is made of sheets of iron which have been laminated (separated by thin sheets of electrically insulating material). The layers of iron and insulator ar
- June 2022, Paper 2, Q2(a)(ii) (2 marks): The permeance of a magnetic circuit can be compared to the conductivity of an electrical circuit. Suggest and explain a change to the generator in Fig. 2.1 whic
- June 2022, Paper 2, Q2(b)(i) (3 marks): The cross-sectional area A of the iron core inside the coil is 1.5 × 10–4 m2. Explain, without calculation, how the maximum emf across the 220-turn coil can be
- June 2022, Paper 2, Q2(b)(ii) (2 marks): The emf ε across each turn of the coil is given by the equation ε = 2πfφmaxsin 2πft Use the equation and data from Fig. 2.2 and part (b) (i) to calculate the ma
- June 2022, Paper 2, Q4(a)(ii) (2 marks): 0.040 m of the copper wire is within the uniform magnetic field which acts perpendicularly to the wire. The reading on the balance changes by 1.4 gram when the
- June 2022, Paper 2, Q4(a)(iii) (3 marks): The student records the balance reading for a range of current values. She plots a graph of balance reading (y-axis) against current (x-axis). Explain how she c
- June 2022, Paper 2, Q4(b)(i) (2 marks): A wire of length 0.90 m carries an alternating current of frequency 50 Hz. The tension in the wire can be changed using weights as indicated in Fig. 4.2. 50 Hz
- November 2021, Paper 1, Q23 (1 mark): The diagram is a section through part of an electrical linear motor. The motor contains a 50-turn coil of diameter 1.8 cm carrying a current of 0.16 A in a radi
- November 2021, Paper 1, Q39(a)(i) (1 mark): Explain why the rotor will turn clockwise when coil 1 pole is a S and coil 2 pole is a N and coil 3 is off. [1]
- November 2021, Paper 1, Q39(a)(ii) (2 marks): In Fig. 39.1b the rotor has rotated 90° aligning between coils 3 and 1. Coil 2 is off, coil 1 pole is a S and coil 3 pole is a N. Complete the path of the singl
- November 2021, Paper 1, Q39(b) (3 marks): Explain each of the following design features of the motor: 1 The stator is made of iron. 2 The stator is laminated (made of layers of iron separated by thin la
- November 2021, Paper 1, Q39(c) (2 marks): For this motor, suggest how to control each of the following. 1 The rate of rotation of the rotor. 2 The force that acts to turn the rotor. 1 2 [2]
- November 2021, Paper 2, Q5(e) (4 marks): A powerful magnet is fixed to the side of the mass as shown in Fig. 5.2. An aluminium sheet is placed below the mass. The friction between the mass and the meta
- November 2020, Paper 1, Q25 (1 mark): The input current I to a simple transformer varies with time t as shown in the graph. I / A 0 t / s A B C D At which point in time A, B, C or D shown on the gra
- November 2020, Paper 1, Q29 (1 mark): Which is the best estimate of the e.m.f. induced across the plane’s wingtips? A 240 mV B 650 mV C 740 mV D 2030 mV Your answer [1]
- November 2020, Paper 1, Q30 (1 mark): For horizontal flight at the position shown, in which direction should the plane fly to experience maximum induced e.m.f. from the Earth’s magnetic field? A All
- November 2020, Paper 3, Q4(a)(i) (1 mark): peak potential difference V V = V [1]
- November 2020, Paper 3, Q4(a)(ii) (1 mark): frequency f f = Hz [1]
- November 2020, Paper 3, Q4(b)(i) (2 marks): Use Fig. 4.3 to explain the student’s reasoning. [2]
- November 2020, Paper 3, Q4(b)(ii) (2 marks): The actual ratio of turns for the transformer is 5 4 . Suggest and explain a reason for this difference. [2]
- November 2020, Paper 3, Q4(c) (2 marks): The current in the primary coil is I1 and the current in the secondary coil is I2. Show that the maximum current in the secondary coil is given by the relations
- November 2020, Paper 3, Q4(d)(i) (3 marks): Estimate the maximum flux through the secondary coil. maximum flux = Wb [3] 17 The student now uses a different set of C-cores which have a greater overall leng
- November 2020, Paper 3, Q4(d)(ii) (2 marks): Complete the diagram by adding two lines which represent the flux in the core at the instant shown. [2]
- November 2020, Paper 3, Q4(d)(iii) (1 mark): State the effect of increasing the length of the magnetic circuit of the transformer. [1] Another student has a faulty set of apparatus such that the C-cores do
- November 2020, Paper 3, Q4(d)(iv) (6 marks): Explain how a small air gap affects the magnetic circuit in Fig. 4.4 and why the core is made of vertically stacked laminated sheets rather than a solid block o
- June 2019, Paper 1, Q24 (1 mark): The graph shows how the flux linkage N Φ through a coil changes with time when the coil is moved into a magnetic field. N Φ 0 0 t0 time Which of the following g
- June 2019, Paper 1, Q33(a)(i) (2 marks): Calculate the voltage across the lamp on the secondary coil. voltage = V [2]
- June 2019, Paper 1, Q33(a)(ii) (2 marks): Calculate the current flowing in the primary coil. current = A [2]
- June 2019, Paper 1, Q33(b) (1 mark): Real transformers are not ideal because of energy losses. State one reason for energy losses in transformers. [1]
- June 2019, Paper 2, Q3(a) (4 marks): A bar magnet is dropped through a vertically mounted coil connected to a data-logger, as shown in Fig. 3.1. S to data-logger magnet N coil Fig. 3.1 The e.m.f. r
- June 2019, Paper 2, Q3(b) (4 marks): An aluminium disk, mounted horizontally on a low-friction pivot, is placed between the poles of a strong magnet, as shown in Fig. 3.3. There is a uniform magnet
- June 2019, Paper 2, Q3(c)(i) (4 marks): Explain what the student means by ‘decreases exponentially’ and, using ideas from part (b), explain whether you would expect the speed of the disk to decrease i
- June 2018, Paper 1, Q17 (1 mark): What is the current in the secondary coil? A 1.5 A B 3.0 A C 4.0 A D 6.0 A Your answer [1]
- June 2018, Paper 1, Q18 (1 mark): What is the best estimate for the rate of change of flux in the transformer core? 0.12 Wb s−1 A 0.12 T m−2 s−1 B 12 Wb s−1 C D 12 T m−2 s−1 Your answer [1]
- June 2018, Paper 1, Q40(b) (6 marks): Fig. 40.1 shows a simplified diagram of a d.c. motor with permanent magnets. Fig. 40.2 shows the graph of current in the coil against frequency of rotation for
- June 2017, Paper 1, Q21 (1 mark): Which of the following changes doubles the flux in a magnetic circuit? 1 doubling the permeance 2 doubling the current-turns 3 halving the circuit length A 1, 2
- June 2017, Paper 1, Q22 (1 mark): An aluminium ring is free to move on a steel rod. When the power supply is on, the ring floats. steel rod aluminium ring power floating above supply the coil co
- June 2017, Paper 1, Q23 (1 mark): Which is the best estimate of the current in the secondary coil? 1 A 4 A 1 B 2 A C 2 A D 4 A Your answer [1]
- June 2017, Paper 1, Q24 (1 mark): Which is the best estimate of the current in the primary coil? 1 A 4 A 1 B 2 A C 2 A D 4 A Your answer [1]
- June 2017, Paper 3, Q3(a)(i) (2 marks): Draw, on Fig. 3.2, at least three lines to represent the magnetic field in the region between the magnetic poles when the current in the wire is zero. [2]
- June 2017, Paper 3, Q3(a)(ii) (2 marks): Explain why the balance reading changes to a new value when the wire carries a current. [2]
- June 2017, Paper 3, Q3(b)(iv) (3 marks): Use the graph to estimate the value of the B‑field between the faces of the slab magnets. B = mT [3]
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? Every OCR A-Level Physics B paper.
Rather write your answers by hand on iPad? Plumi marks them against the same mark schemes.