EEE - Circuit Theorems in AC Analysis Quiz (or) MCQ

1 .

Referring to the given circuit, find Z_TH for the part of the circuit that is external to RL.

A)

43.7 ∠21.4° Ω

B)

43.7 ∠68.6° Ω

C)

12.9 ∠68.6° Ω

D)

129 ∠21.4° Ω

Correct Answer : 43.7 ∠68.6° Ω

2 .

For the circuit shown, determine Z_TH for the portion of the circuit external to RL.

A)

1.44 ∠-33.7° kΩ

B)

6.67 ∠-333.7° kΩ

C)

14.4 ∠-56.3° kΩ

D)

66.7 ∠-33.7° kΩ

Correct Answer : 6.67 ∠-333.7° kΩ

3 .

Referring to the given circuit, what is V_TH if VS = 12 ∠0° V?

A)

4.69 ∠38.7° V

B)

6 ∠0° V

C)

9.38 ∠38.7° V

D)

12 ∠0° V

Correct Answer : 9.38 ∠38.7° V

4 .

Referring to the given circuit, find Z_TH if VS is 180° V.

A)

9.38 ∠-51.3° kΩ

B)

9.82 ∠-51.3° kΩ

C)

19.2 ∠-38.3° kΩ

D)

180 ∠-38.3° kΩ

Correct Answer : 9.38 ∠-51.3° kΩ

5 .

Determine V_TH when R1 is 180 Ω and XL is 90 Ω.

A)

12.2∠0° V

B)

13.5∠63.4° V

C)

122∠0° V

D)

135∠63.4° V

Correct Answer : 13.5∠63.4° V

6 .

The two basic components of a Thevenin equivalent ac circuit are

A)

The equivalent voltage source and the equivalent series resistance

B)

The equivalent voltage source and the equivalent parallel resistance

C)

The equivalent voltage source and the equivalent series impedance

D)

The equivalent voltage source and the equivalent parallel impedance

Correct Answer : The equivalent voltage source and the equivalent series impedance

7 .

In order to get maximum power transfer from a capacitive source, the load must have an impedance that is the complex conjugate of the source impedance.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : True

8 .

Determine V_TH for the circuit external to RL in the given figure.

A)

135 ∠0° V

B)

135 ∠63.4° V

C)

13.5 ∠0° V

D)

13.5 ∠63.4° V

Correct Answer : 13.5 ∠63.4° V

9 .

An equivalent circuit is one that produces the same voltage and current to a given load as the original circuit that it replaces.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : True

10 .

A Thevenin ac equivalent circuit always consists of an equivalent ac voltage source and an equivalent capacitance.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

11 .

Referring to the given circuit, find Z_TH if R is 15 kΩ and RL is 38 kΩ.

A)

9.38 ∠-51.3° kΩ

B)

19.2 ∠-38.3° kΩ

C)

89.82 ∠-51.3° kΩ

D)

180 ∠-38.3° kΩ

Correct Answer : 9.38 ∠-51.3° kΩ

12 .

The Norton equivalent current is

A)

The current through the load

B)

The open-current from the source

C)

The short circuit current

D)

None of the above

Correct Answer : The short circuit current

13 .

Norton's theorem provides a method for the reduction of any ac circuit to an equivalent form consisting of an equivalent voltage source in series with an equivalent impedance.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

14 .

Thevenin's theorem provides a method for the reduction of any ac circuit to an equivalent form consisting of an equivalent current source in parallel with an equivalent impedance.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

15 .

The Thevenin equivalent voltage is

A)

The open circuit voltage

B)

Equal to the source voltage

C)

The same as the load voltage

D)

None of the above

Correct Answer : The open circuit voltage

16 .

If two currents are in the same direction at any instant of time in a given branch of a circuit, the net current at that instant

A)

Is zero

B)

Is the sum of the two currents

C)

Is the difference between the two currents

D)

Cannot be determined

Correct Answer : Is the sum of the two currents

17 .

Norton's theorem gives_____

A)

An equivalent current source in series with an equivalent impedance

B)

An equivalent voltage source in series with an equivalent impedance

C)

An equivalent voltage source in parallel with an equivalent impedance

D)

An equivalent current source in parallel with an equivalent impedance

Correct Answer : An equivalent current source in parallel with an equivalent impedance

18 .

Referring to the given circuit, how much power, in watts, is delivered to the speaker at the determined frequency if VS = 4.5 VRMS?

A)

2.26 mW

B)

4.24 mW

C)

226 mW

D)

424 mW

Correct Answer : 424 mW

19 .

One circuit is equivalent to another, in the context of Thevenin's theorem, when the circuits produce the same voltage.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

20 .

For the given circuit, find V_TH for the circuit external to RL.

A)

4.69 ∠38.7° V

B)

6 ∠0° V

C)

4.69 ∠51.3° V

D)

469 ∠38.7° mV

Correct Answer : 4.69 ∠38.7° V

21 .

Like Thevenin's theorem, Norton's theorem provides a method of reducing a more complex circuit to a simpler, more manageable form for analysis.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : True

22 .

The superposition theorem is useful for the analysis of single-source circuits.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

23 .

For the circuit given, determine the Thevenin voltage as seen by RL.

A)

0.574 ∠16.7° V

B)

0.574 ∠-16.7° V

C)

5.74 ∠16.7° V

D)

5.74 ∠-16.7° V

Correct Answer : 5.74 ∠-16.7° V

24 .

Determine the frequency at which the maximum power is transferred from the amplifier to the speaker in the given figure.

A)

1,027 Hz

B)

6,330 Hz

C)

10,270 Hz

D)

63,330 Hz

Correct Answer : 1,027 Hz

25 .

The superposition theorem is useful for circuit analysis only in ac circuits.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : False

26 .

In order to get maximum power transfer from a capacitive source, the load must

A)

Be as capacitive as it is inductive

B)

Have a capacitive reactance equal to circuit resistance

C)

Have an impedance that is the complex conjugate of the source impedance

D)

None of the above

Correct Answer : Have an impedance that is the complex conjugate of the source impedance

27 .

In applying the superposition theorem,

A)

All sources are considered independently

B)

All sources are considered simultaneously

C)

The sources are considered one at a time with all others replaced by their internal impedance

D)

The sources are considered one at a time with all others replaced by their internal resistance

Correct Answer : The sources are considered one at a time with all others replaced by their internal impedance

28 .

Referring to the given circuit, what is Z_TH if R1 is changed to 220 Ω?

A)

46 ∠12.1° Ω

B)

46 ∠77.9° Ω

C)

225 ∠12.1° Ω

D)

225 ∠77.9° Ω

Correct Answer : 46 ∠77.9° Ω

29 .

Determine V_TH if R1 is changed to 3.3 kΩ

A)

0.463 ∠39.5° V

B)

0.574 ∠16.7° V

C)

4.63 ∠16.7° V

D)

4.63 ∠39.5° V

Correct Answer : 4.63 ∠39.5° V

30 .

Referring to the given figure, determine Z_TH as seen by RL if R1 is changed to 3.3 kΩ.

A)

1488 ∠-70.7° Ω

B)

1828 ∠-50.2° Ω

C)

3859 ∠-31.2° Ω

D)

5180 ∠-50.5° Ω

Correct Answer : 1828 ∠-50.2° Ω

31 .

Referring to the given circuit, determine Z_TH as seen by RL.

A)

956 ∠-48.5° Ω

B)

1444 ∠-48.5° Ω

C)

1444 ∠-73.3° Ω

D)

4176 ∠-73.3° Ω

Correct Answer : 1444 ∠-48.5° Ω

32 .

In an ac circuit, power to the load peaks at the frequency at which the load impedance is the complex conjugate of the output impedance.

A)

True

B)

False

C)

Can Not Say

D)

None of the above

Correct Answer : True

33 .

Referring to the given circuit, L

A)

Must be in parallel with RL

B)

Has no effect on the result

C)

Must be placed in parallel with VS

D)

Must have a reactance equal to XC

Correct Answer : Has no effect on the result

34 .

___ and ____ theorems provide methods for reducing a circuit to a simple equivalent form for easier analysis.

A)

Thevenin's, Norton's

B)

Thevenin's and Ohm's theorems

C)

Newton's and Norton's theorems

D)

None of the above

Correct Answer : Thevenin's, Norton's

35 .

What do you mean by Norton's equivalent current?

A)

total current between two specified terminals in a given circuit.

B)

the open-circuit current between two specified terminals in a given circuit.

C)

the short-circuit current between two specified terminals in a given circuit

D)

None of the above

Correct Answer : the short-circuit current between two specified terminals in a given circuit

36 .

A)

50fÎ©-j50 Î©

B)

100 Î© -j50

C)

100Î©+j50 Î©

D)

50 Î© -j100 Î©