Question 1

For an RLC ac circuit,the rms current is 10 A.If the impedance is 12 kΩ when the voltage leads the current by 39°,find the average power of the circuit.

Accepted Answer

A) 930 kW 
B) 47 kW 
C) 93 kW 
D) 190 kW 
A) 930 kW 
B) 47 kW 
C) 93 kW 
D) 190 kW

Question 2

Which one of the phasor diagrams shown below best represents a series LRC 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 3

A series LRC circuit consists of a 12.0-mH inductor,a 15.0-µF capacitor,a resistor,and a 110-V (rms)ac voltage source.If the impedance of this circuit is 45.0 Ω at resonance,what is its impedance at a frequency twice the resonance frequency?

Accepted Answer

The answer of A series LRC circuit consists of a...

Question 4

A series LRC ac circuit has a peak current of 1.0 A with a frequency of 54 kHz.If the resistance of the circuit is 51 kΩ,the capacitance of the circuit is 19 μF,and the inductance of the circuit is 25 μH,determine the average power of the circuit.

Accepted Answer

A) 26 kW 
B) 77 kW 
C) 7.7 kW 
D) 4.1 kW 
A) 26 kW 
B) 77 kW 
C) 7.7 kW 
D) 4.1 kW

Question 5

A series circuit consists of ac source,a 90-Ω resistor,a 0.80-H inductor,and an 80-μF capacitor.The frequency of the source is adjusted so that the capacitive reactance is equal to twice the inductive reactance.What is the frequency of the source?

Accepted Answer

A) 14 Hz 
B) 13 Hz 
C) 16 Hz 
D) 17 Hz 
E) 19 Hz 
A) 14 Hz 
B) 13 Hz 
C) 16 Hz 
D) 17 Hz 
E) 19 Hz

Question 6

An LRC series circuit has R = 15.0 Ω,L = 25.0 mH,and C = 30.0 μF.The circuit is connected to a 120-V (rms)ac source with frequency 200 Hz.
(a)What is the impedance of the circuit?
(b)What is the rms current in the circuit?
(c)What is the rms voltage across the resistor?
(d)What is the rms voltage across the inductor?
(e)What is the rms voltage across the capacitor?

Accepted Answer

(a)15.8 Ω

Question 7

When an LRC series circuit is at resonance,which one of the following statements about that circuit is accurate? (There may be more than one correct choice.)

Accepted Answer

A) The impedance has its maximum value. 
B) The reactance of the inductor is zero. 
C) The reactance of the capacitor is zero. 
D) The reactance due to the inductor and capacitor has its maximum value. 
E) The current amplitude is a maximum. 
A) The impedance has its maximum value. 
B) The reactance of the inductor is zero. 
C) The reactance of the capacitor is zero. 
D) The reactance due to the inductor and capacitor has its maximum value. 
E) The current amplitude is a maximum.

Question 8

The phase angle of an LRC series circuit with an inductive reactance of 200 Ω,a resistor of 200 Ω and a certain capacitor at 1000 Hz is 40.0°.What is the value of the capacitance in this circuit?

Accepted Answer

A) 1.95 µF 
B) 2.95 µF 
C) 3.95 µF 
D) 4.95 µF 
E) 5.95 µF 
A) 1.95 µF 
B) 2.95 µF 
C) 3.95 µF 
D) 4.95 µF 
E) 5.95 µF

Question 9

An LRC ac series circuit with R = 15 Ω,L = 25 mH,and C = 30 μF,is attached to a 100-V (rms)ac power supply.The frequency of the power supply is adjusted so that the circuit is in resonance.
(a)What is the rms current in the circuit?
(b)What is the power dissipated by the circuit?

Accepted Answer

The answer of An LRC ac series circuit with R...

Question 10

A series circuit consists of a 50-Hz ac source,a 40-Ω resistor,a 0.30-H inductor,and a 60-μF capacitor.The rms current in the circuit is measured to be 1.6 A.What is the power factor of the circuit?

Accepted Answer

A) 0.70 
B) 0.66 
C) 0.63 
D) 0.59 
E) 0.56 
A) 0.70 
B) 0.66 
C) 0.63 
D) 0.59 
E) 0.56

Question 11

The phase angle of an LRC series circuit with an inductive reactance of 200 Ω and a capacitive reactance of 100 Ω is 40.0°.What is the value of the resistor in this circuit?

Accepted Answer

A) 100 Ω 
B) 119 Ω 
C) 156 Ω 
D) 200 Ω 
E) 265 Ω 
A) 100 Ω 
B) 119 Ω 
C) 156 Ω 
D) 200 Ω 
E) 265 Ω

Question 12

What is the average power dissipated by a 25-Ω resistor in an LRC series ac circuit for which the power factor is equal to 0.25 and the maximum voltage of the ac source is 8.0 V?

Accepted Answer

A) 0.040 W 
B) 0.32 W 
C) 0.16 W 
D) 0.62 W 
E) 0.080 W 
A) 0.040 W 
B) 0.32 W 
C) 0.16 W 
D) 0.62 W 
E) 0.080 W

Question 13

A series LRC circuit consists of an ac voltage source of amplitude 75.0 V and variable frequency,a 12.5-µF capacitor,a 5.00-mH inductor,and a 35.0-Ω resistor.
(a)To what angular frequency should the ac source be set so that the current amplitude has its largest value?
(b)Under the conditions of part (a),what is the maximum current amplitude?
(c)Suppose that the voltage source is set to twice the angular frequency needed in part (a).What will be the current amplitude in this case?

Accepted Answer

(a)4.00 ×

Question 14

In a series LRC circuit,the frequency at which the circuit is at resonance is f0.If you double the resistance,the inductance,the capacitance,and the voltage amplitude of the ac source,what is the new resonance frequency?

Accepted Answer

A) 4 f0 
B) 2 f0 
C) f0 
D) f0/2 
E) f0/4 
A) 4 f0 
B) 2 f0 
C) f0 
D) f0/2 
E) f0/4

Question 15

An ac series circuit consists of a voltage source of frequency 60 Hz and voltage amplitude V,a   resistor,and a capacitor of capacitance   What must be the source voltage amplitude V for the average electrical power consumed in the resistor to be 989 W? There is no inductance in the circuit.

Accepted Answer

The answer of An ac series circuit consists of a...

Question 16

The phase angle of an LRC series circuit with a capacitive reactance of 40 Ω,a resistor of 100 Ω and a certain inductor at 1000 Hz is 40.0°.What is the value of the inductance in this circuit?

Accepted Answer

A) 11.8 mH 
B) 124 mH 
C) 212 mH 
D) 61.9 mH 
E) 19.7 mH 
A) 11.8 mH 
B) 124 mH 
C) 212 mH 
D) 61.9 mH 
E) 19.7 mH

Question 17

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

Accepted Answer

A) 0.097 A 
B) 0.11 A 
C) 0.12 A 
D) 0.14 A 
E) 0.17 A 
A) 0.097 A 
B) 0.11 A 
C) 0.12 A 
D) 0.14 A 
E) 0.17 A

Question 18

A 120-V rms voltage at 1000 Hz is applied to an inductor,a 2.00-μF capacitor and a 100-Ω resistor,all in series.If the rms value of the current in this circuit is 0.680 A,what is the inductance of the inductor?

Accepted Answer

A) 34.2 mH 
B) 35.8 mH 
C) 11.4 mH 
D) 17.9 mH 
E) 22.8 mH 
A) 34.2 mH 
B) 35.8 mH 
C) 11.4 mH 
D) 17.9 mH 
E) 22.8 mH

Question 19

An alternating current is supplied to an electronic component with a warning that the voltage across it should never exceed   What is the highest rms voltage that can be supplied to this component while staying below the voltage limit in the warning?

Accepted Answer

A) 6   V 
B) 12   V 
C) 144 V 
D) 6 V 
A) 6   V 
B) 12   V 
C) 144 V 
D) 6 V

Question 20

For an LRC series circuit containing a resistance of   a capacitance of   and an inductance of   what frequency is needed to minimize the impedance?

Accepted Answer

A) 0.023 kHz 
B) 0.14 kHz 
C) 10 kHz 
D) 1.7 kHz 
A) 0.023 kHz 
B) 0.14 kHz 
C) 10 kHz 
D) 1.7 kHz

Exam 32: Ac Circuits

For an RLC ac circuit,the rms current is 10 A.If the impedance is 12 kΩ when the voltage leads the current by 39°,find the average power of the circuit.

Which one of the phasor diagrams shown below best represents a series LRC circuit driven at resonance?

A series LRC circuit consists of a 12.0-mH inductor,a 15.0-µF capacitor,a resistor,and a 110-V (rms)ac voltage source.If the impedance of this circuit is 45.0 Ω at resonance,what is its impedance at a frequency twice the resonance frequency?

A series LRC ac circuit has a peak current of 1.0 A with a frequency of 54 kHz.If the resistance of the circuit is 51 kΩ,the capacitance of the circuit is 19 μF,and the inductance of the circuit is 25 μH,determine the average power of the circuit.

A series circuit consists of ac source,a 90-Ω resistor,a 0.80-H inductor,and an 80-μF capacitor.The frequency of the source is adjusted so that the capacitive reactance is equal to twice the inductive reactance.What is the frequency of the source?

When an LRC series circuit is at resonance,which one of the following statements about that circuit is accurate? (There may be more than one correct choice.)

The phase angle of an LRC series circuit with an inductive reactance of 200 Ω,a resistor of 200 Ω and a certain capacitor at 1000 Hz is 40.0°.What is the value of the capacitance in this circuit?

An LRC ac series circuit with R = 15 Ω,L = 25 mH,and C = 30 μF,is attached to a 100-V (rms)ac power supply.The frequency of the power supply is adjusted so that the circuit is in resonance. (a)What is the rms current in the circuit? (b)What is the power dissipated by the circuit?

A series circuit consists of a 50-Hz ac source,a 40-Ω resistor,a 0.30-H inductor,and a 60-μF capacitor.The rms current in the circuit is measured to be 1.6 A.What is the power factor of the circuit?

The phase angle of an LRC series circuit with an inductive reactance of 200 Ω and a capacitive reactance of 100 Ω is 40.0°.What is the value of the resistor in this circuit?

What is the average power dissipated by a 25-Ω resistor in an LRC series ac circuit for which the power factor is equal to 0.25 and the maximum voltage of the ac source is 8.0 V?

In a series LRC circuit,the frequency at which the circuit is at resonance is f0.If you double the resistance,the inductance,the capacitance,and the voltage amplitude of the ac source,what is the new resonance frequency?

An ac series circuit consists of a voltage source of frequency 60 Hz and voltage amplitude V,a resistor,and a capacitor of capacitance What must be the source voltage amplitude V for the average electrical power consumed in the resistor to be 989 W? There is no inductance in the circuit.

The phase angle of an LRC series circuit with a capacitive reactance of 40 Ω,a resistor of 100 Ω and a certain inductor at 1000 Hz is 40.0°.What is the value of the inductance in this circuit?

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

A 120-V rms voltage at 1000 Hz is applied to an inductor,a 2.00-μF capacitor and a 100-Ω resistor,all in series.If the rms value of the current in this circuit is 0.680 A,what is the inductance of the inductor?

An alternating current is supplied to an electronic component with a warning that the voltage across it should never exceed What is the highest rms voltage that can be supplied to this component while staying below the voltage limit in the warning?

For an LRC series circuit containing a resistance of a capacitance of and an inductance of what frequency is needed to minimize the impedance?

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In a series LRC circuit,the frequency at which the circuit is at resonance is f₀.If you double the resistance,the inductance,the capacitance,and the voltage amplitude of the ac source,what is the new resonance frequency?