The transformer: past paper questions
Real questions on the transformer
The newest 20 of 58 written questions. Open one to see it on the real paper.
- 0625/41 · May/June 2026 · Q10c(ii)[2]
A transformer in the power station steps up the voltage from 25 000 V to 400 000 V. The transformer has 240 turns on the primary coil. Calculate the number of turns on the secondary coil of the transformer. number of turns =
See it on the paper → - 0625/43 · May/June 2026 · Q8a[3]
A teacher uses the arrangement shown in Figure 8.1 to demonstrate how an intruder alarm works. soft-iron bar clamp and stand battery S coil of wire pivot soft-iron arm bell circuit contacts insulator Switch S is connected to a door. When the door is open, switch S is open. When the door is closed, switch S is closed. C...
See it on the paper → - 0625/43 · May/June 2026 · Q8b(i)[2]
Calculate the voltage V s across the secondary coil. V s = V
See it on the paper → - 0625/43 · May/June 2026 · Q8b(ii)[3]
A student connects the primary coil of the transformer to a d.c. supply. Explain why there is no voltage across the secondary coil.
See it on the paper → - 0625/32 · February/March 2026 · Q9b[3]
The charger includes a transformer. The voltage to the primary coil of the transformer V p is 240 V. The secondary voltage V s for the transformer is 16 V. The number of turns on the primary coil N p is 900. Calculate the number of turns on the secondary coil N s for the transformer. number of turns on secondary coil =
See it on the paper → - 0625/42 · February/March 2026 · Q8a(i)[2]
Calculate the input voltage in the step-down transformer. input voltage = V
See it on the paper → - 0625/42 · February/March 2026 · Q8a(ii)[3]
A 2.2 kW kettle is connected to the secondary coil of the transformer. Calculate the current in the primary coil of the step-down transformer. Assume the transformer is 100% efficient. current = A
See it on the paper → - 0625/42 · February/March 2026 · Q8b(i)[1]
State the equation for power loss in electricity transmission.
See it on the paper → - 0625/42 · February/March 2026 · Q8b(ii)[2]
Explain how the step-up transformer reduces power losses during electricity transmission.
See it on the paper → - 0625/31 · October/November 2025 · Q8b[3]
The television uses a transformer. The input voltage (V p ) to the transformer is 120 V. The number of turns (N p ) on the input coil is 560. The number of turns (N s ) on the output coil is 70. Calculate the output voltage (V s ) of the transformer. output voltage = V
See it on the paper → - 0625/33 · October/November 2025 · Q8a[2]
A coal-fired power station is far from a city. The electricity generated by the power station is transmitted to the city at a high voltage. State two advantages of high-voltage transmission of electricity.
See it on the paper → - 0625/33 · October/November 2025 · Q8b[2]
In the city, transformers reduce the high voltage. Fig. 8.1 shows one of these transformers. transformer black cooling fins ground Fig. 8.1 Transformers become hot when they reduce the high voltage. There are black cooling fins on the casing which contains the transformer. Explain why the fins are black.
See it on the paper → - 0625/33 · October/November 2025 · Q8c[3]
Describe the construction and materials of a simple step-down transformer. You may draw a labelled diagram as part of your answer.
See it on the paper → - 0625/31 · May/June 2025 · Q9c[3]
The router uses a transformer. The number of turns N p on the primary coil of the transformer is 3600. The primary voltage V p to the transformer is 240 V. The secondary voltage V s of the transformer is 12 V. Calculate the number of turns N s on the secondary coil of the transformer. number of turns on secondary coil...
See it on the paper → - 0625/41 · May/June 2025 · Q8c(i)[3]
Explain the advantages of transmitting electricity at high voltages. (i)
See it on the paper → - 0625/41 · May/June 2025 · Q8c(ii)[2]
A power station generates electricity at 25 000 V. A transformer steps up the voltage to 300 000 V. The primary coil of the step-up transformer has 450 turns. Calculate the number of turns N s on the secondary coil of the transformer. N s =
See it on the paper → - 0625/43 · May/June 2025 · Q9a(i)[3]
There is an alternating current in the primary coil. Describe how an alternating current is produced in the secondary coil.
See it on the paper → - 0625/43 · May/June 2025 · Q9a(ii)[2]
A step-up transformer has a turns ratio of 1 : 20. The voltage across the primary coil is 12 V. Calculate the voltage across the secondary coil. voltage across secondary coil =
See it on the paper → - 0625/32 · February/March 2025 · Q10c(i)[1]
State a suitable material for the transformer core.
See it on the paper → - 0625/32 · February/March 2025 · Q10c(ii)[1]
State the term used to describe coil X in Fig. 10.2.
See it on the paper →
What examiners said
Comprehensive responses • Many candidates displayed good knowledge of the transformer equation and were able to transfer data from the question to the equation. The vast majority of these candidates were then able to rearrange the transformer equation to give the number of turns on the secondary coil as 60. Limited responses • Some candidates were unable to rearrange the transformer equation to g...
— Examiner report, February/March 2026, 0625/32 Q9(b) (Cambridge)
Comprehensive responses • Most candidates were able to calculate the input voltage to the transformer. Limited responses • Some candidates did not correctly rearrange the equation to make input voltage the subject. • A few candidates were unable to recall the equation relating turns ratio to voltage ratio.
— Examiner report, February/March 2026, 0625/42 Q8(a)(i) (Cambridge)
Comprehensive responses • A few candidates correctly recalled the equation IpVp = IsVs, rearranged it to make primary current the subject, substituted the power (in Watts) for IsVs, and recorded their answer to a minimum of two significant figures. Limited responses • Some candidates correctly converted the power output from 2.2 kW to 2200 W. • Some candidates were confused about how to use the d...
— Examiner report, February/March 2026, 0625/42 Q8(a)(ii) (Cambridge)
Past papers, syllabus and examiner reports © UCLES (Cambridge University Press & Assessment). Questions are matched to topics from the official syllabus. AssessPro is independent and not endorsed by Cambridge.