Physics: An Introduction Chapter 24 -- Practice Questions

Chapter 24: Alternating Current Circuits
Practice Questions

The AC peak voltage in a circuit is 170 volts. What is the RMS voltage?

220V

170 V

120 V

100 V

If the RMS current in the above question is 20 amps what is the peak current?

20 amps

28 amps

38 amps

40 amps

If the AC circuit in questions 1 and 2 is purely resistive what is its resistance?

2 ohms

6 ohms

60 ohms

600 ohms

In questions 1, 2, and 3 what would be the average power in the circuit?

24 watts

240 watts

2400 watts

3145 watts

Which of the following represents the relationship between voltage and current in a AC resistive circuit.

Which of the following represents the relationship between voltage and current in a AC inductive circuit.

Which of the following represents the relationship between voltage and current in a AC capacitive circuit.

What is the reactance of a 0.5 H inductor connected to a 60 Hz AC source?

188 ohms

122 ohms

78 ohms

40 ohms

What is the reactance of a 1 microfarad capacitor connected to a 60 Hz AC source?

26 ohms

261 ohms

2653 ohms

26543 ohms

10.

What would be the reactance of the inductor in question 8 if the AC source were 6000Hz.?

1100 ohms

1754 ohms

10000 ohms

18850 ohms

11.

What would be the reactance of the capacitor in question 9 if it was connected to a 6000 Hz?

27 ohms

291 ohms

2005 ohms

2010 ohms

12.

If the 0.5 H inductor and the 1 microfarad capacitor in the previous questions are connected in series with a 100 ohm resistor and connected to a 60 Hz AC source what is the impedance of the combination?

100 ohms

122 ohms

2466 ohms

18823 ohms

13.

In the previous question what would be the answer if the source was 6000 Hz?

100 ohms

122 ohms

2466 ohms

18823 ohms

14.

At what frequency would the impedance of the circuit in the previous question be a minimum?

225 Hz

550 Hz

750 Hz

1000 Hz

15.

If the peak voltage in the above question is 170 volts, what is the peak current?

0.50 amps

1.7 amps

1.82 amps

2.414 amps

16.

If the frequency of the AC circuit above is 100 Hz what would be the power factor ?

0.08

17.

What is the average power in the circuit in question 16?

0.9 W

1.8 W

11.2 W

22.4

18.

What is the RMS voltage across the resistor in the circuit in question 16?

9.4 V

29.4 V

120 V

1149.1 V

19.

What is the RMS voltage across the inductor in the circuit in question 16?

9.4 V

29.4 V

120 V

149.1 V

20.

What is the RMS voltage across the capacitor in the circuit in question 16?

9.4 V

29.4 V

120 V

149.1 V

21.

What is the phase angle for the circuit in question 16?

0^o

45^o

60^o

86^o

90^o

22.

The following data windows control the above LCR circuit. You can select different values for R and change the frequency by entering new values for f and pressing TAB. What is the resonant frequency of this circuit?

R= ohms frequency: Hz I= amps

112 Hz

224 Hz

232 Hz

238 Hz

242 Hz

275 Hz

23.

What is the voltage in the circuit in question 22?

10 volts

50 volts

100 volts

120 volts

24.

If the inductance in the circuit in question 22 is 30 mH what is the capacitance?

10 microF

15 microF

20 microF

30 microF

25.

In the circuit above the capacitor is used to

isolate the currents in the two circuits.

to filter out DC currents while allowing AC curents to pass.

to filter out AC currents while allowing DC curents to pass.