The d.c. motor: past paper questions
Real questions on the d.c. motor
The newest 20 of 58 written questions. Open one to see it on the real paper.
- 0625/42 · May/June 2026 · Q3b[1]
At another time, the temperature of the water leaving the shower is higher. The power supplied to the water remains constant. Suggest one reason for this increase in temperature.
See it on the paper → - 0625/43 · May/June 2026 · Q9b(i)[2]
Explain how the split-ring commutator allows the coil to rotate continuously.
See it on the paper → - 0625/43 · May/June 2026 · Q9b(ii)[1]
Explain the purpose of the brushes.
See it on the paper → - 0625/41 · October/November 2025 · Q6a[2]
State two advantages of using optical fibres in high-speed data transmission compared to electrical signals sent on copper wires.
See it on the paper → - 0625/43 · October/November 2025 · Q7a(i)[1]
Explain the function of the slip rings and brushes.
See it on the paper → - 0625/43 · October/November 2025 · Q7a(ii)[3]
Describe how an alternating current is generated in the lamp.
See it on the paper → - 0625/43 · October/November 2025 · Q7a(iii)[2]
State two possible changes that cause a larger maximum current in the lamp.
See it on the paper → - 0625/43 · October/November 2025 · Q7b(i)[1]
Determine how many revolutions the coil has made, from time = 0 to E. number of revolutions =
See it on the paper → - 0625/43 · October/November 2025 · Q7b(ii)[3]
Fig. 7.3 shows the end view of the position of the plane of the coil at time = 0. The coil is rotating anti‑clockwise. N S axis of rotation slip rings Fig. 7.3 On Fig. 7.4, draw four lines to match the coil position to the times A, B, C and D. The coil is viewed from the front. Each coil position may be used once, more...
See it on the paper → - 0625/42 · May/June 2025 · Q8a(i)[2]
State the names of components: P and Q
See it on the paper → - 0625/32 · February/March 2025 · Q4a[4]
Describe how the power station generates electrical power from the chemical energy stored in biofuels.
See it on the paper → - 0625/32 · February/March 2025 · Q4b[2]
State one advantage and one disadvantage, apart from cost, of generating electrical power using biofuels compared with generating electrical power using fossil fuels. advantage
See it on the paper → - 0625/42 · February/March 2025 · Q8c[4]
Two magnets and a cell are used to make a simple electric motor as shown in Fig. 8.2. L N magnets S K M J cell Fig. 8.2 Describe the function of parts J, K, L and M. J K L M
See it on the paper → - 0625/43 · October/November 2024 · Q7a(i)[1]
Using Fig. 7.1, calculate the clockwise moment of the weight of the wooden arm about the pivot. clockwise moment = Nm (i)
See it on the paper → - 0625/43 · October/November 2024 · Q7a(ii)[3]
The wooden barrier arm is in equilibrium. The mass of the soft iron bar A is 23 kg. Calculate the distance d between the pivot and the joint holding the soft iron bar A. distance d =
See it on the paper → - 0625/43 · October/November 2024 · Q7b(i)[3]
State and explain what happens to the wooden barrier arm when the switch in the coil circuit is closed. explanation statement
See it on the paper → - 0625/43 · October/November 2024 · Q7b(ii)[2]
The switch is opened. An operator decreases the potential difference across the coil and the switch is closed. State and explain how the effect on the wooden barrier arm compares with the effect in (b)(i). statement explanation (ii)
See it on the paper → - 0625/43 · October/November 2024 · Q7b(iii)[2]
A student suggests that the soft iron bar A is replaced by a steel bar. Explain why a steel bar is less effective than a soft iron bar in the barrier.
See it on the paper → - 0625/43 · May/June 2024 · Q2c(i)[1]
State what is meant by 22% efficiency.
See it on the paper → - 0625/43 · May/June 2024 · Q2c(ii)[2]
Calculate the solar power input to the solar cell. power =
See it on the paper →
What examiners said
Most candidates could correctly identify Q as (carbon) brushes. A significant number of candidates chose split ring or commutator for P and/or Q showing some confusion between a motor and a generator.
— Examiner report, May/June 2025, 0625/42 Q8(a)(i) (Cambridge)
Although many candidates found this item challenging, there were some candidates who gave excellent answers. Common errors included failing to state that the biofuels are burnt to give the thermal energy used to boil water.
— Examiner report, February/March 2025, 0625/32 Q4(a) (Cambridge)
For an advantage, most candidates scored credit by identifying biofuels as a renewable energy source or by stating that biofuels make a much smaller contribution to global warming. Far fewer candidates correctly gave a disadvantage. Answers were often too vague to gain credit, e.g., ‘uses a lot of land’ instead of ‘loss of agricultural land for food production’.
— Examiner report, February/March 2025, 0625/32 Q4(b) (Cambridge)
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