Question 1

Calculate Vout/Vin for the circuit if R = 2.0 kΩ,C = 0.020 μF and V = 140V sin(50000t).
​  
​

Accepted Answer

A) 0.02 
B) 0.45 
C) 0.80 
D) 0.98 
E) 2.2 
A) 0.02 
B) 0.45 
C) 0.80 
D) 0.98 
E) 2.2

Question 2

A high-voltage powerline operates at 500000 V-rms and carries an rms current of 500 A.If the resistance of the cable is 0.050Ω/km,what is the resistive power loss in 200 km of the powerline?

Accepted Answer

A) 250 kW 
B) 500 kW 
C) 1 Megawatt 
D) 2.5 Megawatts 
E) 250 Megawatts 
A) 250 kW 
B) 500 kW 
C) 1 Megawatt 
D) 2.5 Megawatts 
E) 250 Megawatts

Question 3

The phase angle between V and I is

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 4

All three circuits shown below have R = 100 Ω,L = 0.1 H and emf ε = (5.0 V)sin (377 t).Which statement regarding the angular resonance frequencies ωA,ωB and ωC is correct?

Accepted Answer

A) ωC > ωA = ωB 
B) ωC A = ωB 
C) ωA = ωB = ωC 
D) ωB A = ωC 
E) ωB > ωA = ωC 
A) ωC > ωA = ωB 
B) ωC A = ωB 
C) ωA = ωB = ωC 
D) ωB A = ωC 
E) ωB > ωA = ωC

Question 5

The graphs below show the phasors ΔVmax and Imax for five RLC series circuits.The solid arrows represent the voltage phasors,ΔV,and the dashed arrows represent the current phasors,Imax.The graph which represents a circuit where the inductive reactance is greater than the capacitive reactance is

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 6

A series RLC circuit has an impedance of 120Ω and a resistance of 64Ω.What average power is delivered to this circuit when Vrms = 90 volts?

Accepted Answer

A) 36 W 
B) 100 W 
C) 192 W 
D) 360 W 
E) 12 W 
A) 36 W 
B) 100 W 
C) 192 W 
D) 360 W 
E) 12 W

Question 7

A 10-μF capacitor in an LC circuit made entirely of superconducting materials (R = 0 Ω)is charged to 100 μC.Then a superconducting switch is closed.At t = 0 s,plate 1 is positively charged and plate 2 is negatively charged.At a later time,Vab = +10 V.At that time,Vdc is

Accepted Answer

A) 0 V. 
B) 3.54 V. 
C) 5.0 V. 
D) 7.07 V. 
E) 10 V. 
A) 0 V. 
B) 3.54 V. 
C) 5.0 V. 
D) 7.07 V. 
E) 10 V.

Question 8

A 60.0-Hz ac generator with a peak voltage of 110 V drives a series RC circuit with R = 10.0 Ω and C = 300 μF.The peak current in the circuit is

Accepted Answer

A) 8.24 A. 
B) 8.84 A. 
C) 11.0 A. 
D) 12.4 A. 
E) 23.5 A. 
A) 8.24 A. 
B) 8.84 A. 
C) 11.0 A. 
D) 12.4 A. 
E) 23.5 A.

Question 9

A 60.0-Hz ac generator with a peak voltage of 110 V drives a series RL circuit with R = 10.0 Ω and L = 10.0 mH.The power factor,cos φ,is

Accepted Answer

A) −1.00. 
B) −0.936. 
C) +0.943. 
D) +0.936. 
E) +1.00. 
A) −1.00. 
B) −0.936. 
C) +0.943. 
D) +0.936. 
E) +1.00.

Question 10

A 230000 V-rms powerline carries an average power Pavg = 250 MW a distance of 200 km.If the total resistance of the cables is 10 ohms,what is the resistive power loss?

Accepted Answer

A) 1.0 MW 
B) 2.5 MW 
C) 5.4 MW 
D) 12 MW 
E) 10 kW 
A) 1.0 MW 
B) 2.5 MW 
C) 5.4 MW 
D) 12 MW 
E) 10 kW

Question 11

In a parallel RLC circuit,where IR = IR,max sin(ωt),the current through the capacitor,IC,is

Accepted Answer

A) IC = −IC,max sin(ωt). 
B) IC = IC,max sin(ωt). 
C) IC = −IC,max cos(ωt). 
D) IC = IC,max cos(ωt). 
E) IC = IC,max tan(ωt). 
A) IC = −IC,max sin(ωt). 
B) IC = IC,max sin(ωt). 
C) IC = −IC,max cos(ωt). 
D) IC = IC,max cos(ωt). 
E) IC = IC,max tan(ωt).

Question 12

At what frequency will a 50.0-mH inductor have a reactance XL = 700Ω?

Accepted Answer

A) 352 Hz 
B) 777 Hz 
C) 1.25 kHz 
D) 2.23 kHz 
E) 14 kHz 
A) 352 Hz 
B) 777 Hz 
C) 1.25 kHz 
D) 2.23 kHz 
E) 14 kHz

Question 13

An ac power generator produces 50 A (rms)at 3600 V.The voltage is stepped up to 100000 V by an ideal transformer and the energy is transmitted through a long distance power line which has a resistance of 100 ohms.What percentage of the power delivered by the generator is dissipated as heat in the long-distance power line?

Accepted Answer

The answer of An ac power generator produces 50 A...

Question 14

A 10.0-μF capacitor is plugged into a 110 V-rms 60.0-Hz voltage source,with an ammeter in series.What is the rms value of the current through the capacitor?

Accepted Answer

A) 0.202 A (rms) 
B) 0.415 A (rms) 
C) 0.626 A (rms) 
D) 0.838 A (rms) 
E) 0.066 A (rms) 
A) 0.202 A (rms) 
B) 0.415 A (rms) 
C) 0.626 A (rms) 
D) 0.838 A (rms) 
E) 0.066 A (rms)

Question 15

In a parallel RLC circuit,where IR = IR,max sin(ωt),the current through the inductor,IL,is

Accepted Answer

A) IL = −IL,max sin(ωt). 
B) IL = IL,max sin(ωt). 
C) IL = −IL,max cos(ωt). 
D) IL = IL,max cos(ωt). 
E) IL = IL,max tan(ωt). 
A) IL = −IL,max sin(ωt). 
B) IL = IL,max sin(ωt). 
C) IL = −IL,max cos(ωt). 
D) IL = IL,max cos(ωt). 
E) IL = IL,max tan(ωt).

Question 16

The average power input to a series alternating current circuit is minimum when

Accepted Answer

A) there are only a resistor and capacitor in the circuit. 
B) there are only a resistor and inductor in the circuit. 
C) there is only a resistor in the circuit. 
D) XL = XC and the circuit contains a resistor,an inductor and a capacitor. 
E) there is only a capacitor in the circuit. 
A) there are only a resistor and capacitor in the circuit. 
B) there are only a resistor and inductor in the circuit. 
C) there is only a resistor in the circuit. 
D) XL = XC and the circuit contains a resistor,an inductor and a capacitor. 
E) there is only a capacitor in the circuit.

Question 17

Which of the following is true about a diode?

Accepted Answer

A) A diode causes the voltage to shift in phase by 90°,i.e.,a right angle. 
B) A diode has high resistance in one current direction and low resistance in the opposite current direction. 
C) A diode can only be used with a transformer. 
D) All filter circuits contain a diode. 
E) All of the above. 
A) A diode causes the voltage to shift in phase by 90°,i.e.,a right angle. 
B) A diode has high resistance in one current direction and low resistance in the opposite current direction. 
C) A diode can only be used with a transformer. 
D) All filter circuits contain a diode. 
E) All of the above.

Question 18

The graphs below show a voltage phasor at different instances of time.The voltage phasor which shows the instantaneous value of the voltage with the largest magnitude is

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 19

An electric heater draws an average power of 1100 Watts when plugged into a 110 V-rms outlet.Calculate the resistance of the heater and the rms current.

Accepted Answer

A) 11Ω,10 A (rms) 
B) 110Ω,10 A (rms) 
C) 10Ω,11 A (rms) 
D) 10Ω,110 A (rms) 
E) 0.09Ω,11 A (rms) 
A) 11Ω,10 A (rms) 
B) 110Ω,10 A (rms) 
C) 10Ω,11 A (rms) 
D) 10Ω,110 A (rms) 
E) 0.09Ω,11 A (rms)

Question 20

Capacitive reactance XC is given by

Accepted Answer

A) 1/ωC 
B) ωC 
C) ω/C 
D) C/ω 
E) 1/ω2C 
A) 1/ωC 
B) ωC 
C) ω/C 
D) C/ω 
E) 1/ω2C

Exam 33: Alternating-Current Circuits

Calculate Vout/Vin for the circuit if R = 2.0 kΩ,C = 0.020 μF and V = 140V sin(50000t). ​ ​

A high-voltage powerline operates at 500000 V-rms and carries an rms current of 500 A.If the resistance of the cable is 0.050Ω/km,what is the resistive power loss in 200 km of the powerline?

The phase angle between V and I is

All three circuits shown below have R = 100 Ω,L = 0.1 H and emf ε = (5.0 V)sin (377 t).Which statement regarding the angular resonance frequencies ωA,ωB and ωC is correct?

The graphs below show the phasors ΔVmax and Imax for five RLC series circuits.The solid arrows represent the voltage phasors,ΔV,and the dashed arrows represent the current phasors,Imax.The graph which represents a circuit where the inductive reactance is greater than the capacitive reactance is

A series RLC circuit has an impedance of 120Ω and a resistance of 64Ω.What average power is delivered to this circuit when Vrms = 90 volts?

A 10-μF capacitor in an LC circuit made entirely of superconducting materials (R = 0 Ω)is charged to 100 μC.Then a superconducting switch is closed.At t = 0 s,plate 1 is positively charged and plate 2 is negatively charged.At a later time,Vab = +10 V.At that time,Vdc is

A 60.0-Hz ac generator with a peak voltage of 110 V drives a series RC circuit with R = 10.0 Ω and C = 300 μF.The peak current in the circuit is

A 60.0-Hz ac generator with a peak voltage of 110 V drives a series RL circuit with R = 10.0 Ω and L = 10.0 mH.The power factor,cos φ,is

A 230000 V-rms powerline carries an average power Pavg = 250 MW a distance of 200 km.If the total resistance of the cables is 10 ohms,what is the resistive power loss?

In a parallel RLC circuit,where IR = IR,max sin(ωt),the current through the capacitor,IC,is

At what frequency will a 50.0-mH inductor have a reactance XL = 700Ω?

A 10.0-μF capacitor is plugged into a 110 V-rms 60.0-Hz voltage source,with an ammeter in series.What is the rms value of the current through the capacitor?

In a parallel RLC circuit,where IR = IR,max sin(ωt),the current through the inductor,IL,is

The average power input to a series alternating current circuit is minimum when

Which of the following is true about a diode?

The graphs below show a voltage phasor at different instances of time.The voltage phasor which shows the instantaneous value of the voltage with the largest magnitude is

An electric heater draws an average power of 1100 Watts when plugged into a 110 V-rms outlet.Calculate the resistance of the heater and the rms current.

Capacitive reactance XC is given by

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Filters

Calculate V_out/V_in for the circuit if R = 2.0 kΩ,C = 0.020 μF and V = 140V sin(50000t).

All three circuits shown below have R = 100 Ω,L = 0.1 H and emf ε = (5.0 V)sin (377 t).Which statement regarding the angular resonance frequencies ω_A,ω_B and ω_C is correct?

A series RLC circuit has an impedance of 120Ω and a resistance of 64Ω.What average power is delivered to this circuit when V_rms = 90 volts?

A 10-μF capacitor in an LC circuit made entirely of superconducting materials (R = 0 Ω)is charged to 100 μC.Then a superconducting switch is closed.At t = 0 s,plate 1 is positively charged and plate 2 is negatively charged.At a later time,V_ab = +10 V.At that time,V_dc is

A 230000 V-rms powerline carries an average power P_avg = 250 MW a distance of 200 km.If the total resistance of the cables is 10 ohms,what is the resistive power loss?

In a parallel RLC circuit,where I_R = IR_,max sin(ωt),the current through the capacitor,I_C,is

At what frequency will a 50.0-mH inductor have a reactance X_L = 700Ω?

In a parallel RLC circuit,where I_R = IR_,max sin(ωt),the current through the inductor,I_L,is

Capacitive reactance X_C is given by