Alternating currents: past paper questions
Real questions on alternating currents
The newest 20 of 69 written questions. Open one to see it on the real paper.
- 9702/41 · May/June 2025 · Q6a(i)[1]
State what is meant by rectification.
See it on the paper → - 9702/41 · May/June 2025 · Q6b(i)[2]
where A and B are constants. Determine the values of A and B. Give a unit with your answer for A. A = unit –1 The variation of V IN with t can be represented by V IN = A cos Bt
See it on the paper → - 9702/41 · May/June 2025 · Q6b(ii)[1]
Determine the type of rectification produced by the circuit in Fig. 6.1.
See it on the paper → - 9702/42 · May/June 2025 · Q8a(i)[1]
State the type of rectification produced by the circuit of Fig. 8.1. (a) (i)
See it on the paper → - 9702/42 · May/June 2025 · Q8a(ii)[1]
Calculate V 0 . V 0 = V
See it on the paper → - 9702/42 · May/June 2025 · Q8b(i)[2]
Determine the peak power P 0 in the resistor. P 0 = W
See it on the paper → - 9702/42 · May/June 2025 · Q8b(ii)[3]
On Fig. 8.3, sketch the variation of the power P in the resistor with t between t = 0 and t = 2T. P 0 P 1 2 P 0 0 T t 2T 0
See it on the paper → - 9702/42 · May/June 2025 · Q8b(iii)[2]
Use the answer in (b)(ii) to explain why the mean power in the resistor is 4 P 0 .
See it on the paper → - 9702/42 · May/June 2025 · Q8b(iv)[1]
Use the information in (b)(iii) to determine the r.m.s. value of V OUT . r.m.s. voltage = V
See it on the paper → - 9702/43 · May/June 2025 · Q6a(i)[1]
State what is meant by rectification.
See it on the paper → - 9702/43 · May/June 2025 · Q6a(ii)[1]
State the purpose of capacitor C. (ii)
See it on the paper → - 9702/43 · May/June 2025 · Q6b(i)[2]
where A and B are constants. Determine the values of A and B. Give a unit with your answer for A. A = unit –1 The variation of V IN with t can be represented by V IN = A cos Bt
See it on the paper → - 9702/43 · May/June 2025 · Q6b(ii)[1]
Determine the type of rectification produced by the circuit in Fig. 6.1.
See it on the paper → - 9702/43 · May/June 2025 · Q6b(iii)[2]
On Fig. 6.3, draw the circuit diagram for the components inside the rectification circuit. W Y X Z
See it on the paper → - 9702/41 · October/November 2024 · Q6a(i)[1]
State what is meant by rectification of an alternating voltage.
See it on the paper → - 9702/41 · October/November 2024 · Q6a(ii)[2]
State the difference between half-wave rectification and full-wave rectification.
See it on the paper → - 9702/41 · October/November 2024 · Q6b(i)[2]
Complete Fig. 6.1 to show a circuit that produces half-wave rectification of an alternating input voltage V IN to produce output voltage V OUT across the resistor R. V IN R C V OUT Fig. 6.1 (b) (i)
See it on the paper → - 9702/41 · October/November 2024 · Q6b(ii)[1]
State the purpose of the capacitor C in the circuit of Fig. 6.1.
See it on the paper → - 9702/41 · October/November 2024 · Q6c(ii)[3]
Determine the resistance of R. (ii) resistance = Ω
See it on the paper → - 9702/42 · October/November 2024 · Q8a[1]
State what is meant by the frequency of an alternating current.
See it on the paper →
What examiners said
Candidates found some aspects of this sketch difficult. There were many correct shapes, but a large number of responses did not have an appropriate scale on the y-axis.
— Examiner report, October/November 2023, 9702/43 Q7(b) (Cambridge)
Stronger candidates were able to achieve full credit. Weaker candidates often produced expressions that were not dimensionally consistent with power.
— Examiner report, October/November 2023, 9702/43 Q7(c)(i) (Cambridge)
Many candidates did not recognise the difference between the r.m.s. of a sinusoidally varying current and one (as in this question) that varied as a square wave. The relationship I0 / 2 was often used here in error because candidates did not realise that it applies only to a sinusoidal current. Again, weaker candidates often gave answers that were not dimensionally consistent with a current.
— Examiner report, October/November 2023, 9702/43 Q7(c)(ii) (Cambridge)
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