The a.c. generator: past paper questions
Real questions on the a.c. generator
The newest 6 of 6 written questions. Open one to see it on the real paper.
- 0972/42 · May/June 2022 · Q8a[1]
Calculate the time period of the a.c. time period =
See it on the paper → - 0972/41 · May/June 2019 · Q7c(ii)[2]
the ammeter reading. reading =
See it on the paper → - 0972/41 · May/June 2019 · Q7d[2]
The temperature of component X increases. State and explain what happens to the ammeter reading.
See it on the paper → - 0972/41 · May/June 2019 · Q8a(i)[3]
Explain why rotating the coil produces an output voltage.
See it on the paper → - 0972/41 · May/June 2019 · Q8a(ii)[2]
State the position of the rotating coil when the alternating output voltage is at a maximum value and explain why the maximum output occurs at this position.
See it on the paper → - 0972/41 · May/June 2019 · Q8b[3]
A lamp and an open switch are connected in series to the output terminals of the a.c. generator. The switch is closed and the lamp lights up. The student has to apply a greater force on the handle. Explain why a greater force is needed to keep the lamp lit.
See it on the paper →
What examiners said
Candidates who knew that the time period is 1/f and were able to calculate 1/60 to 2 significant figures were awarded credit. Common errors were not converting the fraction to a decimal, incorrect rounding to 0.016 s resulting in a significant figure error, attempting to measure the length of the time period on the diagram and assuming that was the time in seconds and omitting the unit.
— Examiner report, May/June 2022, 0972/42 Q8(a) (Cambridge)
There were many good answers to these two parts. In (i), almost all candidates used the equation for resistors in parallel correctly and only occasionally was the final reciprocal ignored.
— Examiner report, May/June 2019, 0972/41 Q7(c) (Cambridge)
Most candidates knew what was happening but some stated that the resistance of the thermistor increased as the temperature increased. Where full credit was not awarded, usually the effect on the resistance of the thermistor was stated, but how this affected the resistance of the complete circuit and hence the current and the ammeter reading was not.
— Examiner report, May/June 2019, 0972/41 Q7(d) (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.