Below you will find a set of 5 conceptual and numerical revision questions selected randomly from lots of questions I have put together covering the material in Chapter 29, "Alternating-Current Circuits". This includes questions on ac generators, alternating current in resistors, inductors and capacitors, phasors, RCL circuits with a generator and transformers. When you have finished the quiz, click on the "Submit Quiz" button at the bottom and within seconds it will be automatically graded and the results returned to you!

To select a new set of questions click on the "Reload" or "Refresh" button on your browser. You may find some of the questions duplicated but that's the nature of a random selection. Try it a few times ... it's not fattening and you may learn something!

Many thanks to Mark Wood for producing the quiz-maker code.

Q1: If the frequency in the circuit below is doubled, the inductance of the inductor will:

increase by a factor of 2
remain unchanged
decrease by a factor of 2
increase by a factor of 4
decrease by a factor of 4

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Q2: The voltage across and the current through a single circuit element connected to an ac generator is shown in the graph.

Which one of the following statements concerning this circuit element is true?

The element is a resistor.
The element is a capacitor.
The element is an inductor.
The element could be an inductor or a resistor.
The element could be an inductor or a capacitor.

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Q3: A series RCL circuit is driven by a 1.0 kHz oscillator. The circuit parameters are V(rms) = 12 V, L = 5.0 mH, C = 4.0 μF, and R = 20 Ω. Under these conditions the current

lags the voltage by 22.8°.
leads the voltage by 22.8°.
lags the voltage by 41.6°.
leads the voltage by 41.6°.
is in phase with the voltage.

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Q4: An ac generator supplies an rms (not peak) voltage of 180 V at 60 Hz. It is connected in series with a 0.5 H inductor, a 6 μF capacitor and a 300 Ω resistor. What is the impedance of the circuit?

150 Ω
190 Ω
360 Ω
390 Ω
440 Ω

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Q5: A power plant produces a voltage of 6000 V and 150 A. The voltage is stepped up to 240,000 V by a transformer before it is transmitted to a substation. The resistance of the transmission line between the power plant and the substation is 75 Ω. What is the current in the transmission line from the plant to the substation?

3.8 A
5.2 A
6.4 A
7.0 A
7.5 A

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