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9702/41/M/J/24 · question 1 of 2 in this topic

Question 7

7(b)(i)2 marks

A sinusoidal alternating supply is connected to a bridge of four diodes with a load resistor R across the output . Fig. 7.2 shows the variation of V_OUT with time t.

The load resistor R has a resistance of 370 Ω. Show that the maximum power dissipated in R is 0.22 W.

Fig. 7.1 — see the question text for what it shows
Fig. 7.2 — see the question text for what it shows

Show The result is given, so every step of the reasoning is what earns the marks.

Your answer

Suggested time: 3 min

7(b)(ii)3 marks

A sinusoidal alternating supply feeds a bridge rectifier with load resistor R of resistance 370 Ω; the rectified output voltage V_OUT has a peak value of about 9.0 V and touches zero every 0.02 s over the interval t = 0 to 0.08 s . The maximum power dissipated in R is 0.22 W.

On Fig. 7.3, sketch the variation with t of the power P dissipated in R.

Fig. 7.2 — see the question text for what it shows
Fig. 7.3 — see the question text for what it shows

Your answer

Suggested time: 5 min

7(b)(iii)1 mark

A sinusoidal alternating supply feeds a bridge rectifier with a load resistor R of resistance 370 Ω. The maximum power dissipated in R is 0.22 W.

Calculate the mean power dissipated in R.

Calculate Show your working. The method can earn marks even when the final value is wrong, and a bare answer often cannot.

Your answer

Suggested time: 2 min

7(c)2 marks

A sinusoidal alternating supply feeds a bridge rectifier circuit with a load resistor R of resistance 370 Ω, and the mean power dissipated in R has been calculated. The circuit of Fig. 7.1 is now disconnected, and R is connected directly across the power supply.

Explain, without calculation, how the mean power now dissipated in R compares with the answer in (b)(iii).

Fig. 7.1 — see the question text for what it shows

Explain Give reasons, not just what happens. Each distinct reason is usually worth a mark.

Your answer

Suggested time: 3 min

9702/41/M/J/24Cambridge International AS & A Level Physics 9702 · May/June 2024 · Paper 4 variant 1 · sit the whole paper