EEE - RL Circuits Quiz (or) MCQ | Questions and Answers

1 .

What do you know about RL circuit?

A)

conductor

B)

an device composed of resistors and inductors driven by a voltage or current source

C)

an electric circuit composed of resistors and inductors driven by a voltage or current source

D)

None of the above

Correct Answer : an electric circuit composed of resistors and inductors driven by a voltage or current source

2 .

RL circuit is also known as:

A)

inductor

B)

conductor

C)

resistorâ€“inductor circuit or RL filter or RL network

D)

All of the above

Correct Answer : resistorâ€“inductor circuit or RL filter or RL network

3 .

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

A)

Halves

B)

Doubles

C)

Remains constant

D)

Cannot be determined without values

Correct Answer : Cannot be determined without values

4 .

A filter passes certain frequencies and rejects others.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : True

5 .

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

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : True

6 .

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)

942 Ω

C)

1,200 Ω

D)

1,526 Ω

Correct Answer : 1,526 Ω

7 .

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

A)

Increases

B)

Decreases

C)

Does not change

D)

Cannot be determined without values

Correct Answer : Decreases

8 .

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

Correct Answer : 3.84 ∠20.6° V

9 .

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

A)

Should be increased

B)

Should be constant

C)

Should be decreased

D)

Cannot be determined without values

Correct Answer : Should be decreased

10 .

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

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

11 .

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

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

12 .

What is the relationship between current flowing in the circuit I, current through resistor I_R and inductor I_L in RL circuit?

A)

I= I_L= I_R

B)

I_L+ I_L=I

C)

I_L- I_R=I

D)

None of the above

Correct Answer : I= I_L= I_R

13 .

The apply voltage in RL circuit must be equal to:

A)

Difference of voltage drop

B)

Voltage drop across resistor

C)

Sum of voltage drop across resistor and inductor

D)

All of the above

Correct Answer : Sum of voltage drop across resistor and inductor

14 .

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

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : True

15 .

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)

0.564

B)

6.76

C)

55.7

D)

564

Correct Answer : 0.564

16 .

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

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : True

17 .

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

Correct Answer : 129 ∠68.6° Ω

18 .

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

A)

0 VA

B)

6 VA

C)

12 VA

D)

24 VA

Correct Answer : 12 VA

19 .

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)

2 V

B)

26.0 V

C)

18.4 V

D)

20 V

Correct Answer : 26.0 V

Explaination :

20 .

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

A)

Increases

B)

Decreases

C)

Does not change

D)

Cannot be determined without values

Correct Answer : Increases

21 .

The impedance of an RL circuit varies inversely with frequency.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

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

Correct Answer : 0.2

23 .

What is the relationship between the impedance of series Z, resistance (R) and inductive reactance (X_L) of the RL circuit?

A)

Z = (R² + X_L²)^0.5

B)

Z = (R² + X_L²)⁵

C)

Z = (R³ + X_L²)^0.5

D)

Z = (R² + X_L³)^1\2

Correct Answer : Z = (R² + X_L²)^0.5

24 .

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

Correct Answer : Increases

25 .

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

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : True

26 .

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

Correct Answer : 55.15 Ω

27 .

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)

8.74 µA

C)

874 mA

D)

874 µA

Correct Answer : 8.74 mA

28 .

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)

12 mA

B)

32 mA

C)

120 mA

D)

152 mA

Correct Answer : 120 mA

29 .

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

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

30 .

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)

218 ∠-76° mS

B)

12.60 ∠-76° mS

C)

12.18 ∠76° mS

D)

12.18 ∠-76° mS

Correct Answer : 12.18 ∠-76° mS

31 .

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)

4.24 A

B)

6 A

C)

42.4 A

D)

424 mA

Correct Answer : 4.24 A

32 .

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

C)

Can Not Say

D)

None of the above

Correct Answer : False

33 .

How many watt power(P) dissipated by the resistor(R) in the form of heat?

A)

P = I²R (watts)

B)

P = IR² (watts)

C)

P = I^0.2R (watts)

D)

None of the above

Correct Answer : P = I²R (watts)

34 .

Reactive power is measured in the unit of ___.

A)

Volt-Watt-Reactive (VAR)

B)

Volt-Amps-Resistance (VAR)

C)

Volt-Amps-Reactive (VAR)

D)

None of the above

Correct Answer : Volt-Amps-Reactive (VAR)

35 .

What is the instantaneous power deliver (P) by voltage source (V)?

A)

P = VI

B)

P = VI ²

C)

P = V/I

D)

None of the above

Correct Answer : P = VI ²