Question 1

At what frequency is the reactance of a 20.0-mH inductor equal to 120 Ω?

Accepted Answer

A) 318 Hz 
B) 637 Hz 
C) 796 Hz 
D) 955 Hz 
E) 1110 Hz 
A) 318 Hz 
B) 637 Hz 
C) 796 Hz 
D) 955 Hz 
E) 1110 Hz D

Question 2

What is the reactance of a 20-mH inductor at a frequency of 60 Hz?

Accepted Answer

A) 7.5 Ω 
B) 0.13 Ω 
C) 1.2 Ω 
D) 1.2 mΩ 
E) 7.5 mΩ 
A) 7.5 Ω 
B) 0.13 Ω 
C) 1.2 Ω 
D) 1.2 mΩ 
E) 7.5 mΩ A

Question 3

A 120-V rms voltage is applied across a 6.0-μF capacitor and a series combination of a 100-Ω resistor.If the frequency of the power source is 60 Hz,what is the rms value of the current in the circuit?

Accepted Answer

A) 0.26 A 
B) 0.36 A 
C) 0.46 A 
D) 0.56 A 
E) 0.76 A 
A) 0.26 A 
B) 0.36 A 
C) 0.46 A 
D) 0.56 A 
E) 0.76 A A

Question 4

A pure inductor is connected to an ac power supply.In this circuit,the current

Accepted Answer

A) leads the voltage by 90°. 
B) is in phase with the voltage. 
C) lags the voltage by 45°. 
D) lags the voltage by 90°. 
E) leads the voltage by 45°. 
A) leads the voltage by 90°. 
B) is in phase with the voltage. 
C) lags the voltage by 45°. 
D) lags the voltage by 90°. 
E) leads the voltage by 45°.

Question 5

In the circuit shown in the figure,the 60-Hz ac source has a voltage amplitude of 120 V,the capacitive reactance is  
The inductive reactance is  
And the resistance is  
What is the rms current in the circuit?

Accepted Answer

A) 0.11 A 
B) 0.13 A 
C) 0.14 A 
D) 0.17 A 
E) 0.20 A 
A) 0.11 A 
B) 0.13 A 
C) 0.14 A 
D) 0.17 A 
E) 0.20 A

Question 6

A 120-V rms signal at 60 Hz is applied across a series combination of a 30-mH inductor and a 100-Ω resistor.What is the rms value of the voltage across the resistor?

Accepted Answer

A) 120 V 
B) 60 V 
C) 100 V 
D) 150 V 
E) 0.70 V 
A) 120 V 
B) 60 V 
C) 100 V 
D) 150 V 
E) 0.70 V

Question 7

The reactance of a capacitor is  
At a frequency of  
What is the capacitance?

Accepted Answer

A) 0.066 μF 
B) 0.42 μF 
C) 2.6 μF 
D) 0.093 μF 
A) 0.066 μF 
B) 0.42 μF 
C) 2.6 μF 
D) 0.093 μF

Question 8

A resistance of 55 Ω,a capacitor of capacitive reactance 30 Ω,and an inductor of inductive reactance 30 Ω are connected in series to a 110-V rms,60-Hz power source.What rms current flows in this circuit?

Accepted Answer

A) 2.0 A 
B) less than 2.0 A 
C) more than 2.0 A 
D) none of the given answers 
A) 2.0 A 
B) less than 2.0 A 
C) more than 2.0 A 
D) none of the given answers

Question 9

The figure shows a series ac circuit.The inductor has a reactance of 60 Ω and an inductance of 150 mH.A 50-Ω R and a capacitor C whose reactance is 90 Ω are also in the circuit,and the rms current in the circuit is 1.5 A.What is the rms voltage of the source?

Accepted Answer

A) 87 V 
B) 84 V 
C) 81 V 
D) 78 V 
E) 75 V 
A) 87 V 
B) 84 V 
C) 81 V 
D) 78 V 
E) 75 V

Question 10

What rms current flows in a 60-mH inductor when 120-V rms ac at a frequency of 20 kHz is applied to it?

Accepted Answer

A) 8.0 mA 
B) 16 mA 
C) 24 mA 
D) 32 mA 
A) 8.0 mA 
B) 16 mA 
C) 24 mA 
D) 32 mA

Question 11

A series RLC circuit has a 100-Ω resistor,a 0.100-μF capacitor and a 2.00-mH inductor connected across a 120-V rms ac voltage source operating at 1000/π Hz.What is the resonant frequency of this circuit?

Accepted Answer

A) 70.7 kHz 
B) 17.9 kHz 
C) 22.5 kHz 
D) 35.3 kHz 
E) 11.3 kHz 
A) 70.7 kHz 
B) 17.9 kHz 
C) 22.5 kHz 
D) 35.3 kHz 
E) 11.3 kHz

Question 12

The current through a 50-Ω resistor is I = (0.80 A) sin(240t),where t is measured in seconds. How much power on average is dissipated in the resistor?

Accepted Answer

A) 16 W 
B) 32 W 
C) 45 W 
D) 64 W 
A) 16 W 
B) 32 W 
C) 45 W 
D) 64 W

Question 13

At what frequency will a 14.0-mH coil have 14.0 Ω of inductive reactance?

Accepted Answer

A) 1000 Hz 
B) 505 Hz 
C) 257 Hz 
D) 159 Hz 
A) 1000 Hz 
B) 505 Hz 
C) 257 Hz 
D) 159 Hz

Question 14

A series circuit contains an 80-μF capacitor,a 0.020-H inductor,and a switch.The resistance of the circuit is negligible.Initially,the switch is open,the capacitor voltage is 50 V,and the current in the inductor is zero.At time t = 0 s,the switch is closed.When the current in the circuit is 1.5 A,what is the charge on the capacitor?

Accepted Answer

A) 2000 µC 
B) 2500 µC 
C) 3000 µC 
D) 3500 µC 
E) 4000 µC 
A) 2000 µC 
B) 2500 µC 
C) 3000 µC 
D) 3500 µC 
E) 4000 µC

Question 15

In the figure,which of the phasor diagrams represents a series RLC circuit driven at resonance?

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 4 
E) 5 
A) 1 
B) 2 
C) 3 
D) 4 
E) 5

Question 16

In the circuit shown in the figure,the 60-Hz ac source has a voltage amplitude of 120 V,the capacitive reactance is  
The inductive reactance is  
And the resistance is  
What is the inductance L of the inductor?

Accepted Answer

A) 770 mH 
B) 1,700 mH 
C) 2,900 mH 
D) 3,700 mH 
E) 4,800 mH 
A) 770 mH 
B) 1,700 mH 
C) 2,900 mH 
D) 3,700 mH 
E) 4,800 mH

Question 17

If the maximum voltage of an ac signal is 8.0 V,what is the rms value of this voltage?

Accepted Answer

A) 2.8 V 
B) 5.7 V 
C) 6.2 V 
D) 4.0 V 
E) 16.0 V 
A) 2.8 V 
B) 5.7 V 
C) 6.2 V 
D) 4.0 V 
E) 16.0 V

Question 18

What is the reactance of a 1.0-mH inductor at 60 Hz?

Accepted Answer

A) 0.19 Ω 
B) 0.38 Ω 
C) 2.7 Ω 
D) 5.3 Ω 
A) 0.19 Ω 
B) 0.38 Ω 
C) 2.7 Ω 
D) 5.3 Ω

Question 19

A 120-V rms voltage is applied across a 6.0-μF capacitor.If the frequency of the generator is 60 Hz,what is the rms value of the current in the circuit?

Accepted Answer

A) 0.47 A 
B) 0.37 A 
C) 0.071 A 
D) 0.17 A 
E) 0.27 A 
A) 0.47 A 
B) 0.37 A 
C) 0.071 A 
D) 0.17 A 
E) 0.27 A

Question 20

What is the phase angle between the voltages of the inductor and capacitor in a RLC series circuit?

Accepted Answer

A) 0° 
B) 45° 
C) 90° 
D) 180° 
E) 270° 
A) 0° 
B) 45° 
C) 90° 
D) 180° 
E) 270°

Exam 24: Alternating-Current Circuits

At what frequency is the reactance of a 20.0-mH inductor equal to 120 Ω?

What is the reactance of a 20-mH inductor at a frequency of 60 Hz?

A 120-V rms voltage is applied across a 6.0-μF capacitor and a series combination of a 100-Ω resistor.If the frequency of the power source is 60 Hz,what is the rms value of the current in the circuit?

A pure inductor is connected to an ac power supply.In this circuit,the current

In the circuit shown in the figure,the 60-Hz ac source has a voltage amplitude of 120 V,the capacitive reactance is The inductive reactance is And the resistance is What is the rms current in the circuit?

A 120-V rms signal at 60 Hz is applied across a series combination of a 30-mH inductor and a 100-Ω resistor.What is the rms value of the voltage across the resistor?

The reactance of a capacitor is At a frequency of What is the capacitance?

A resistance of 55 Ω,a capacitor of capacitive reactance 30 Ω,and an inductor of inductive reactance 30 Ω are connected in series to a 110-V rms,60-Hz power source.What rms current flows in this circuit?

The figure shows a series ac circuit.The inductor has a reactance of 60 Ω and an inductance of 150 mH.A 50-Ω R and a capacitor C whose reactance is 90 Ω are also in the circuit,and the rms current in the circuit is 1.5 A.What is the rms voltage of the source?

What rms current flows in a 60-mH inductor when 120-V rms ac at a frequency of 20 kHz is applied to it?

A series RLC circuit has a 100-Ω resistor,a 0.100-μF capacitor and a 2.00-mH inductor connected across a 120-V rms ac voltage source operating at 1000/π Hz.What is the resonant frequency of this circuit?

The current through a 50-Ω resistor is I = (0.80 A) sin(240t),where t is measured in seconds. How much power on average is dissipated in the resistor?

At what frequency will a 14.0-mH coil have 14.0 Ω of inductive reactance?

In the figure,which of the phasor diagrams represents a series RLC circuit driven at resonance?

In the circuit shown in the figure,the 60-Hz ac source has a voltage amplitude of 120 V,the capacitive reactance is The inductive reactance is And the resistance is What is the inductance L of the inductor?

If the maximum voltage of an ac signal is 8.0 V,what is the rms value of this voltage?

What is the reactance of a 1.0-mH inductor at 60 Hz?

A 120-V rms voltage is applied across a 6.0-μF capacitor.If the frequency of the generator is 60 Hz,what is the rms value of the current in the circuit?

What is the phase angle between the voltages of the inductor and capacitor in a RLC series circuit?

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