Question
Suppose we would like the average power dissipated in the resistor to be $5.00 \mathrm{~W}$. Should the resistance be increased or decreased, assuming that the same $\mathrm{AC}$ generator is used? Find the required value of $R$.
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In a purely resistive circuit, the power factor \(cos(\phi)\) is 1. Show more…
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When a certain resistor is connected to an ac generator with a maximum voltage of 15 $\mathrm{V}$ , the average power dissipated in the resistor is 22 $\mathrm{W}$ . (a) What is the resistance of the resistor? (b) What is the rms current in the circuit? (c) We know that $P_{\mathrm{av}}=I_{\mathrm{rms}}^{2} R,$ and hence it seems that reducing the resistance should reduce the average power. On the other hand, we also know that $P_{\mathrm{av}}=V_{\mathrm{rms}}^{2} / R,$ which suggests that reducing $R$ increases $P_{\mathrm{av}} .$ Which conclusion is correct? Explain.
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Alternating-Current Circuits and Machines
Analysis of AC Resistor Circuits
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