## Network Theory MCQ Set 1

1. The power generated by a machine increases _____________ percent from single phase to two phase.

a) 40.4

b) 41.4

c) 42.4

d) 43.4

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2. The percentage of power increased from single phase to three phase is?

a) 50

b) 100

c) 150

d) 200

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3. When the power factor is __________ the power becomes zero 100 times a second in a 50Hz supply.

a) 0

b) 1

c) 2

d) 3

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4. Which motors are called self-starting motors?

a) single phase

b) two phase

c) three phase

d) four phase

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5. In three phase system, the three voltages (currents) differ in phase by __________electrical degrees from each other in a particular sequence.

a) 30

b) 60

c) 90

d) 120

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6. In a two phase generator, the armature has two distinct windings that are displaced __________ apart.

a) 45⁰

b) 90⁰

c) 135⁰

d) 180⁰

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7. In three phase system at any given instant, the algebraic sum of three voltages must be?

a) 0

b) 1

c) 2

d) 3

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8. Phase sequence depends on the?

a) field

b) rotation of the field

c) armature

d) rotation of the armature

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9. If RR^{‘}, YY^{‘} and BB^{‘} constitutes three phase sequence if V^{‘}_{RR} = V_{m}sinωt its corresponding field magnets are in clockwise direction, then V^{‘}_{YY} =?

a) V_{m}sinωt

b) V_{m}sin(ωt+120⁰)

c) V_{m}sin(ωt-120⁰)

d) V_{m}sin(ωt-240⁰)

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^{‘}

_{YY}is V

^{‘}

_{YY}= V

_{m}sin(ωt-120⁰).

10. The value of V^{‘}_{BB} in the question 9 is?

a) V_{m}sin(ωt-240⁰)

b) V_{m}sin(ωt-120⁰)

c) V_{m}sin(ωt+240⁰)

d) V_{m}sinωt

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^{‘}

_{BB}is V

^{‘}

_{BB}= V

_{m}sin(ωt-240⁰). There are only two possible phase sequences; they are RBY and RYB.

## Network Theory MCQ Set 2

1. The driving point function is the ratio of polynomials in s. Polynomials are obtained from the __________ of the elements and their combinations.

a) transform voltage

b) transform current

c) transform impedance

d) transform admittance

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2. The pole is that finite value of S for which N (S) becomes __________

a) 0

b) 1

c) 2

d) ∞

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_{1}, P

_{2}… P

_{m}are called poles of N (S) if N (S) = ∞ at those points. The pole is that finite value of S for which N (S) becomes infinity.

3. A function N (S) is said to have a pole (or zero) at infinity, if the function N (1/S) has a pole (or zero) at S = ?

a) ∞

b) 2

c) 0

d) 1

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^{r}or(S-P)

^{r}is a factor of P(s) or Q(s).

4. The number of zeros including zeros at infinity is __________ the number of poles including poles at infinity.

a) greater than

b) equal to

c) less than

d) greater than or equal to

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5. The poles of driving point impedance are those frequencies corresponding to ___________ conditions?

a) short circuit

b) voltage source

c) open circuit

d) current source

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6. The zeros of driving point impedance are those frequencies corresponding to ___________ conditions?

a) current source

b) open circuit

c) voltage source

d) short circuit

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7. In the driving point admittance function, a zero of Y (s) means a _______of I (S).

a) 1

b) 2

c) 3

d) zero

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8. In the driving point admittance function, a pole of Y (s) means a _______ of V (S).

a) zero

b) 1

c) 2

d) 3

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9. The real part of all zeros and poles must be?

a) positive or zero

b) negative or zero

c) positive

d) negative

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10. Poles or zeros lying on the jω axis must be?

a) complex

b) at least one complex pole

c) at least one complex zero

d) simple

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## Network Theory MCQ Set 3

1. The coefficients of numerator polynomial and the denominator polynomial in a transfer function must be?

a) real

b) complex

c) at least one real coefficient

d) at least one complex coefficient

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2. In a transfer function, the degree of numerator polynomial is ___________ than the degree of the denominator polynomial.

a) greater than

b) less than

c) equal to

d) less than or equal to

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_{21}(s) or Y

_{21}(s) is less than or equal to the degree of the denominator polynomial plus one.

3. The real parts of all poles and zeros in a driving point function must be?

a) zero

b) negative

c) zero or negative

d) positive

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4. If the real part of driving point function is zero, then the pole and zero must be?

a) complex

b) simple

c) one complex pole

d) one complex zero

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5. The degree of the numerator polynomial and denominator polynomial in a driving point function may differ by?

a) 0

b) 1

c) 0 or 1

d) 2

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6. The lowest degree in numerator polynomial and denominator polynomial in a driving point function may differ by at most __________

a) 0

b) 1

c) 2

d) 3

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7. The coefficients in the denominator polynomial of the transfer function must be?

a) positive

b) negative

c) positive or zero

d) negative or zero

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8. The coefficients in the numerator polynomial of the transfer function may be?

a) must be negative

b) must be positive

c) may be positive

d) may be negative

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9. The denominator polynomial in a transfer function may not have any missing terms between the highest and the lowest degree, unless?

a) all odd terms are missing

b) all even terms are missing

c) all even or odd terms are missing

d) all even and odd terms are missing

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10. The degree of numerator polynomial in a transfer function may be as small as _________ independent of the degree of the denominator polynomial.

a) 1

b) 2

c) 0

d) 3

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## Network Theory MCQ Set 4

1. In a three phase alternator, there are __________ independent phase windings or coils.

a) 1

b) 2

c) 3

d) 4

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2. Each coil in three phase alternator has ________________ number of terminals.

a) 2

b) 4

c) 6

d) 8

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3. In wye or star connection, ______________ of the three phases are joined together within the alternator.

a) similar ends

b) opposite ends

c) one similar end, two opposite ends

d) one opposite end, two opposite ends

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4. The voltage between __________ and ___________ is called phase voltage.

a) line and line

b) line and reference

c) neutral point and reference

d) line and neutral point

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5. The voltage between ______________ is called line voltage.

a) line and neutral point

b) line and reference

c) line and line

d) neutral point and reference

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6. Figure below represents three phases of an alternator. The phase voltage for the star connection among the options given below is?

a) V_{RY}

b) V_{RN}

c) V_{YB}

d) V_{BR}

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_{RN}. And V

_{RY}, V

_{YB}and V

_{BR}are not phase voltages.

7. In the figure shown above, what will be the line voltage?

a) V_{BR}

b) V_{BN}

c) V_{RN}

d) V_{YN}

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from one another and acting simultaneously in the cicruit like three independent single phase sources in the same frame of a three phase alternator. Line voltage = V

_{BR}. And V_{RN}, V_{YN}and V_{BN}are not line voltages.8. In the Delta or Mesh connection, there will be __________ number of common terminals.

a) 1

b) 2

c) 3

d) 0

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9. The relation between line voltage and phase voltage in Delta or Mesh connection is?

a) V_{phase} > V_{line}

b) V_{phase} < V_{line}

c) V_{phase} = V_{line}

d) V_{phase} >= V_{line}

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_{phase}= V

_{line}.

10. Which of the following voltage is a phase voltage in delta connection?

a) V_{RN}

b) V_{BR}

c) V_{YN}

d) V_{BN}

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phase differences. V

_{BR}is a phase voltage in delta connection. And V_{RN}, V_{YN}and V_{BN}are not phase voltages.## Network Theory MCQ Set 5

1. The reactive power equation (P_{r}) is?

a) I_{eff}^{2} (ωL)sin2(ωt+θ)

b) I_{eff}^{2} (ωL)cos2(ωt+θ)

c) I_{eff}^{2} (ωL)sin(ωt+θ)

d) I_{eff}^{2} (ωL)cos(ωt+θ)

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_{r}) is P

_{r}=I

_{eff}

^{2}(ωL)sin2(ωt+θ).

2. Reactive power is expressed in?

a) Watts (W)

b) Volt Amperes Reactive (VAR)

c) Volt Ampere (VA)

d) No units

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3. The expression of reactive power (Pr) is?

a) V_{eff}I_{m}sinθ

b) V_{m}I_{m}sinθ

c) V_{eff}I_{eff}sinθ

d) V_{m}I_{eff}sinθ

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_{r}) is V

_{eff}I

_{eff}sinθ Volt Amperes Reactive (VAR). Reactive power =V

_{eff}I

_{eff}sinθ Volt Amperes Reactive (VAR).

4. The power factor is the ratio of ________ power to the ______ power.

a) average, apparent

b) apparent, reactive

c) reactive, average

d) apparent, average

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5. The expression of true power (P_{true}) is?

a) P_{a}sinθ

b) P_{a}cosθ

c) P_{a}tanθ

d) P_{a}secθ

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_{true}) is P

_{a}cosθ. True power = P

_{a}cosθ.

6. The average power (P_{avg}) is expressed as?

a) P_{a}secθ

b) P_{a}tanθ

c) P_{a}cosθ

d) P_{a}sinθ

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_{avg}) is expressed as P

_{a}cosθ. Average power = P

_{a}cosθ.

7. The equation of reactive power is?

a) P_{a}cosθ

b) P_{a}secθ

c) P_{a}sinθ

d) P_{a}tanθ

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_{a}sinθ. Reactive power = P

_{a}sinθ.

8. A sinusoidal voltage v = 50sinωt is applied to a series RL circuit. The current in the circuit is given by I = 25sin (ωt-53⁰). Determine the apparent power (VA).

a) 620

b) 625

c) 630

d) 635

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_{app}= V

_{eff}I

_{eff}= (V

_{m}/√2)×(I

_{m}/√2). On substituting the values V

_{m}= 50, I

_{m}=25, we get apparent power = (50×25)/2 = 625VA.

9. Find the power factor in the question 8.

a) 0.4

b) 0.5

c) 0.6

d) 0.7

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10. In the question 8 determine the average power.

a) 365

b) 370

c) 375

d) 380

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_{avg}= V

_{eff}I

_{eff}cosθ. We know the values of V

_{eff}, I

_{eff}are V

_{eff}= 625 and I

_{eff}– 0.6.So the average power = 625 x 0.6 = 375W.