Physics 9702 · AS & A Level · Characteristics of alternating currents
Characteristics of alternating currents — practice question
The current $I$ in a resistor varies with time $t$ as shown in Fig. 6.1. This current-time change is sinusoidal.
(a)[2]
Explain why power is converted in the resistor even though the current is not flowing in only one direction.
(b)[3]
From the link between root-mean-square (r.m.s.) current and peak current, determine the ratio $\frac{\text{average power converted in the resistor}}{\text{maximum power converted in the resistor}}$.
Worked solution & mark scheme
This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “heating/power depends on $I^2$” …