When the frequency of the voltage applied to a series RL circuit is decreased, the impedance

Cannot be determined without values

When the frequency of the voltage applied to a series RL circuit is increased, the phase angle

Cannot be determined without values

To increase the current in a series RL circuit, the frequency

Cannot be determined without values

If the frequency is halved and the resistance is doubled, the impedance of a series RL circuit

Cannot be determined without values

83 + Mcqs in Rl Circuits in Electronics Page 1 McqOptions

1.	What is the magnitude of the phase angle of a 24 Vac parallel circuit when = 45 and = 1100 ?
A.	0.001°
B.	2.3°
C.	87.6°
D.	89.9°
Answer» C. 87.6°

Discussion

2.	What is the magnitude of the phase angle between the source voltage and current when a 100 mH inductor with an inductive reactance of 6 k and a 1 k resistor are in series with a source?
A.	0.1°
B.	9.0°
C.	61.0°
D.	81.0°
Answer» E.

Discussion

3.	If = 100 and = 100 , then impedance will be
A.	141.4
B.	14.14
C.	100
D.	200
Answer» B. 14.14

Discussion

4.	What is the true power of a 24 Vac parallel circuit when = 45 and = 1100 ?
A.	313.45 W
B.	12.8 W
C.	44.96 W
D.	22.3 W
Answer» C. 44.96 W

Discussion

5.	If a 7.5 k resistance is connected to a 10 k inductive reactance in a series circuit, then the impedance equals 12.5 k .
A.	True
B.	False
Answer» B. False

Discussion

6.	The impedance of a series circuit when = 15 k and = 10 k is approximately equal to ________.
A.	5 k
B.	6 k
C.	18 k
D.	25 k
Answer» D. 25 k

Discussion

7.	The phase angle will decrease in a series circuit if the inductance is increased.
A.	True
B.	False
Answer» C.

Discussion

8.	As frequency decreases in a parallel circuit the impedance also decreases.
A.	True
B.	False
Answer» B. False

Discussion

9.	Phase angle is the difference in phase between the applied voltage (S) and the circuit current ().
A.	True
B.	False
Answer» B. False

Discussion

10.	In a series circuit, a power factor of 0.5 results in less energy conversion to heat than does a power factor of 0.6.
A.	True
B.	False
Answer» B. False

Discussion

11.	If = 20 mS, then = 20.
A.	True
B.	False
Answer» C.

Discussion

12.	As the frequency increases in a series circuit the impedance also increases.
A.	True
B.	False
Answer» B. False

Discussion

13.	The phase angle will increase in a parallel circuit if the resistance is increased.
A.	True
B.	False
Answer» B. False

Discussion

14.	The frequency at which = in an circuit is called the _______________.
A.	cutoff frequency
B.	optimum frequency
C.	bandwidth characteristic
D.	resonant frequency
Answer» B. optimum frequency

Discussion

15.	The phase angle (θ) of a series RL circuit varies directly with frequency.
A.	True
B.	False
Answer» B. False

Discussion

16.	A 470 resistor and a 200 mH coil are in parallel. Both components are across a 1.5 kHz ac source. The total admittance of the circuit, in polar form, is
A.	12.60 –76° mS
B.	12.1876° mS
C.	218 –76° mS
D.	12.18 –76° mS
Answer» E.

Discussion

17.	A 12 k resistor is in series with a 90 mH coil across an 8 kHz ac source. Current flow in the circuit, expressed in polar form, is I = 0.30° mA. The source voltage, expressed in polar form, is
A.	3.8420.6° V
B.	12.820.6° V
C.	0.320.6° V
D.	13.8469.4° V
Answer» B. 12.820.6° V

Discussion

18.	A 47 resistor is in series with an inductive reactance of 120 across an ac source. The impedance, expressed in polar form, is
A.	4768.6°
B.	12068.6°
C.	12931.4°
D.	12968.6°
Answer» E.

Discussion

19.	A power factor of 1 indicates a purely reactive circuit, and a power factor of 0 indicates a purely resistive circuit.
A.	True
B.	False
Answer» C.

Discussion

20.	In a parallel RL circuit, there are 3 A rms in the resistive branch and 3 A rms in the inductive branch. The total rms current is
A.	6 A
B.	424 mA
C.	4.24 A
D.	42.4 A
Answer» D. 42.4 A

Discussion

21.	A 470 Ω resistor and a 200 mH coil are in parallel. Both components are across a 1.5 kHz ac source. The total admittance of the circuit, in polar form, is
A.	12.60 ∠-76° mS
B.	12.18 ∠76° mS
C.	218 ∠-76° mS
D.	12.18 ∠-76° mS
Answer» E.

Discussion

22.	Which of the following power factors results in less energy loss in an RL circuit?
A.	1
B.	0.8
C.	0.4
D.	0.2
Answer» E.

Discussion

23.	If a load is purely inductive and the reactive power is 12 VAR, the apparent power is
A.	0 VA
B.	12 VA
C.	6 VA
D.	24 VA
Answer» C. 6 VA

Discussion

24.	A 47 Ω resistor is in series with an inductive reactance of 120 Ω across an ac source. The impedance, expressed in polar form, is
A.	47 ∠68.6° Ω
B.	120 ∠68.6° Ω
C.	129 ∠31.4° Ω
D.	129 ∠68.6° Ω
Answer» E.

Discussion

25.	A 12 kΩ resistor is in series with a 90 mH coil across an 8 kHz ac source. Current flow in the circuit, expressed in polar form, is I = 0.3 ∠0° mA. The source voltage, expressed in polar form, is
A.	3.84 ∠20.6° V
B.	12.8 ∠20.6° V
C.	0.3 ∠20.6° V
D.	13.84 ∠69.4° V
Answer» B. 12.8 ∠20.6° V

Discussion

26.	When the frequency of the voltage applied to a series RL circuit is decreased, the impedance
A.	Decreases
B.	Increases
C.	Does not change
D.	Cannot be determined without values
Answer» B. Increases

Discussion

27.	A 1.2 kΩ resistor is in series with a 15 mH coil across a 10 kHz ac source. The magnitude of the total impedance is
A.	152.6 Ω
B.	1,526 Ω
C.	1,200 Ω
D.	942 Ω
Answer» C. 1,200 Ω

Discussion

28.	The impedance of an RL circuit varies inversely with frequency.
A.	True
B.	False
Answer» C.

Discussion

29.	When the frequency of the voltage applied to a series RL circuit is increased, the phase angle
A.	Decreases
B.	Increases
C.	Does not change
D.	Cannot be determined without values
Answer» C. Does not change

Discussion

30.	The resistor voltage in an RL circuit is always out of phase with the current.
A.	True
B.	False
Answer» C.

Discussion

31.	When the frequency is decreased, the impedance of a parallel RL circuit Increases
A.	True
B.	False
Answer» C.

Discussion

32.	To increase the current in a series RL circuit, the frequency
A.	Should be increased
B.	Should be decreased
C.	Should be constant
D.	Cannot be determined without values
Answer» C. Should be constant

Discussion

33.	The power factor indicates how much of the apparent power is reactive power.
A.	True
B.	False
Answer» C.

Discussion

34.	A 470 Ω resistor and a coil with 125 Ω inductive reactance are in parallel. Both components are across a 15 V ac voltage source. Current through the inductor is
A.	152 mA
B.	32 mA
C.	12 mA
D.	120 mA
Answer» E.

Discussion

35.	A 3.3 kΩ resistor and a 120 mH coil are in parallel. Both components are across a 2 kHz, 12 V ac source. The total current in the circuit is
A.	8.74 mA
B.	874 mA
C.	874 µA
D.	8.74 µA
Answer» B. 874 mA

Discussion

36.	In an RL circuit, part of the power is resistive and part is reactive.
A.	True
B.	False
Answer» B. False

Discussion

37.	In a series RL circuit, 12 V rms is measured across the resistor, and 14 V rms is measured across the inductor. The peak value of the source voltage is
A.	18.4 V
B.	26.0 V
C.	2 V
D.	20 V
Answer» C. 2 V

Discussion

38.	A 140 Ω resistor is in parallel with an inductor having 60 Ω inductive reactance. Both components are across a 12 V ac source. The magnitude of the total impedance is
A.	5.51 Ω
B.	55.15 Ω
C.	90 Ω
D.	200 Ω
Answer» C. 90 Ω

Discussion

39.	The phase angle (?) of a series RL circuit varies directly with frequency.
A.	True
B.	False
Answer» B. False

Discussion

40.	When the resistor voltage in a series RL circuit becomes less than the inductor voltage, the phase angle
A.	Increases
B.	Decreases
C.	Is not affected
D.	Cannot be determined
Answer» B. Decreases

Discussion

41.	Total current in an RL circuit always lags the source voltage.
A.	True
B.	False
Answer» B. False

Discussion

42.	A 1.5 kΩ resistor and a coil with a 2.2 kΩ inductive reactance are in series across an 18 V ac source. The power factor is
A.	564
B.	0.564
C.	6.76
D.	55.7
Answer» C. 6.76

Discussion

43.	In an RL circuit, the impedance is determined by both the resistance and the inductive reactance combined.
A.	True
B.	False
Answer» B. False

Discussion

44.	When the frequency is decreased, the impedance of a parallel RL circuit
A.	Increases
B.	Decreases
C.	Remains constant
D.	Is not a factor
Answer» C. Remains constant

Discussion

45.	When the frequency of the voltage applied to a series RL circuit is decreased, the impedance decreases
A.	True
B.	False
Answer» B. False

Discussion

46.	A filter passes certain frequencies and rejects others.
A.	True
B.	False
Answer» B. False

Discussion

47.	If the frequency is halved and the resistance is doubled, the impedance of a series RL circuit
A.	Doubles
B.	Halves
C.	Remains constant
D.	Cannot be determined without values
Answer» E.

Discussion

48.	If Y = 20 mS, then Z = 20.
A.	1
B.
Answer» C.

Discussion

49.	The impedance of the circuit in the given circuit is approximately equal to _____.
A.	2 k
B.	750
C.	1.25 k
D.	1 k
Answer» D. 1 k

Discussion

50.	The cutoff frequency of the circuit in the given circuit is approximately equal to _____.
A.	21 Hz
B.	60 Hz
C.	0 Hz
D.	365 Hz
Answer» E.

Discussion

Explore topic-wise MCQs in Electronics.

What is the magnitude of the phase angle of a 24 Vac parallel circuit when = 45 and = 1100 ?

What is the magnitude of the phase angle between the source voltage and current when a 100 mH inductor with an inductive reactance of 6 k and a 1 k resistor are in series with a source?

If = 100 and = 100 , then impedance will be

What is the true power of a 24 Vac parallel circuit when = 45 and = 1100 ?

If a 7.5 k resistance is connected to a 10 k inductive reactance in a series circuit, then the impedance equals 12.5 k .

The impedance of a series circuit when = 15 k and = 10 k is approximately equal to ________.

The phase angle will decrease in a series circuit if the inductance is increased.

As frequency decreases in a parallel circuit the impedance also decreases.

Phase angle is the difference in phase between the applied voltage (S) and the circuit current ().

In a series circuit, a power factor of 0.5 results in less energy conversion to heat than does a power factor of 0.6.

If = 20 mS, then = 20.

As the frequency increases in a series circuit the impedance also increases.

The phase angle will increase in a parallel circuit if the resistance is increased.

The frequency at which = in an circuit is called the _______________.

The phase angle (θ) of a series RL circuit varies directly with frequency.

A 470 resistor and a 200 mH coil are in parallel. Both components are across a 1.5 kHz ac source. The total admittance of the circuit, in polar form, is

A 12 k resistor is in series with a 90 mH coil across an 8 kHz ac source. Current flow in the circuit, expressed in polar form, is I = 0.30° mA. The source voltage, expressed in polar form, is

A 47 resistor is in series with an inductive reactance of 120 across an ac source. The impedance, expressed in polar form, is

A power factor of 1 indicates a purely reactive circuit, and a power factor of 0 indicates a purely resistive circuit.

In a parallel RL circuit, there are 3 A rms in the resistive branch and 3 A rms in the inductive branch. The total rms current is

A 470 Ω resistor and a 200 mH coil are in parallel. Both components are across a 1.5 kHz ac source. The total admittance of the circuit, in polar form, is

Which of the following power factors results in less energy loss in an RL circuit?

If a load is purely inductive and the reactive power is 12 VAR, the apparent power is

A 47 Ω resistor is in series with an inductive reactance of 120 Ω across an ac source. The impedance, expressed in polar form, is

A 12 kΩ resistor is in series with a 90 mH coil across an 8 kHz ac source. Current flow in the circuit, expressed in polar form, is I = 0.3 ∠0° mA. The source voltage, expressed in polar form, is

When the frequency of the voltage applied to a series RL circuit is decreased, the impedance

A 1.2 kΩ resistor is in series with a 15 mH coil across a 10 kHz ac source. The magnitude of the total impedance is

The impedance of an RL circuit varies inversely with frequency.

When the frequency of the voltage applied to a series RL circuit is increased, the phase angle

The resistor voltage in an RL circuit is always out of phase with the current.

When the frequency is decreased, the impedance of a parallel RL circuit Increases

To increase the current in a series RL circuit, the frequency

The power factor indicates how much of the apparent power is reactive power.

A 470 Ω resistor and a coil with 125 Ω inductive reactance are in parallel. Both components are across a 15 V ac voltage source. Current through the inductor is

A 3.3 kΩ resistor and a 120 mH coil are in parallel. Both components are across a 2 kHz, 12 V ac source. The total current in the circuit is

In an RL circuit, part of the power is resistive and part is reactive.

In a series RL circuit, 12 V rms is measured across the resistor, and 14 V rms is measured across the inductor. The peak value of the source voltage is

A 140 Ω resistor is in parallel with an inductor having 60 Ω inductive reactance. Both components are across a 12 V ac source. The magnitude of the total impedance is

The phase angle (?) of a series RL circuit varies directly with frequency.

When the resistor voltage in a series RL circuit becomes less than the inductor voltage, the phase angle

Total current in an RL circuit always lags the source voltage.

A 1.5 kΩ resistor and a coil with a 2.2 kΩ inductive reactance are in series across an 18 V ac source. The power factor is

In an RL circuit, the impedance is determined by both the resistance and the inductive reactance combined.

When the frequency is decreased, the impedance of a parallel RL circuit

When the frequency of the voltage applied to a series RL circuit is decreased, the impedance decreases

A filter passes certain frequencies and rejects others.

If the frequency is halved and the resistance is doubled, the impedance of a series RL circuit

If Y = 20 mS, then Z = 20.

The impedance of the circuit in the given circuit is approximately equal to _____.

The cutoff frequency of the circuit in the given circuit is approximately equal to _____.