250+ TOP MCQs on Apparent Power and Power Factor and Answers

Network Theory Interview Questions and Answers for Experienced people on “Apparent Power and Power Factor”.

1. The highest power factor will be?
A. 1
B. 2
C. 3
D. 4
Answer: A
Clarification: The power factor is useful in determining the useful power transferred to a load. The highest power factor will be 1.

2. If power factor = 1, then the current to the load is ______ with the voltage across it.
A. out of phase
B. in phase
C. 90⁰ out of phase
D. 45⁰ out of phase
Answer: B
Clarification: If power factor = 1, then the current to the load is in phase with the voltage across it because the expression of power factor is power factor = cosθ.

3. In case of resistive load, what is the power factor?
A. 4
B. 3
C. 2
D. 1
Answer: D
Clarification: In case of resistive load, the power factor = 1 as the current to the load is in phase with the voltage across it.

4. If power factor = 0, then the current to a load is ______ with the voltage.
A. in phase
B. out of phase
C. 45⁰ out of phase
D. 90⁰ out of phase
Answer: D
Clarification: If the power factor = 0, then the current to a load is 90⁰ out of phase with the voltage and it happens in case of reactive load.

5. For reactive load, the power factor is equal to?
A. 0
B. 1
C. 2
D. 3
Answer: A
Clarification: For reactive load, the power factor is equal to 0. Power factor = 0 when current to a load is 90⁰ out of phase with the voltage.

6. Average power is also called?
A. apparent power
B. reactive power
C. true power
D. instantaneous power
Answer: C
Clarification: The average power is expressed in watts. It means the useful power transferred from the source to the load, which is also called true power. Average power is also called true power.

7. If we apply a sinusoidal voltage to a circuit, the product of voltage and current is?
A. true power
B. apparent power
C. average power
D. reactive power
Answer: B
Clarification: If we apply a sinusoidal voltage to a circuit, the product of voltage and current is apparent power. The apparent power is expressed in volt amperes or simply VA.

8. The expression of apparent power (Papp) is?
A. VmIm
B. VmIeff
C. VeffIeff
D. VeffIm
Answer: C
Clarification: In case of sinusoidal voltage applied to the circuit, the product of voltage and the current is not the true power or average power and it is apparent power. The expression of apparent power (Papp) is Papp = VeffIeff.

9. The power factor=?
A. sinθ
B. cosθ
C. tanθ
D. secθ
Answer: B
Clarification: The expression of power factor is power factor= cosθ. As the phase angle between the voltage and the current increases the power factor decreases.

10. The power factor is the ratio of ________ power to the ______ power.
A. average, apparent
B. apparent, reactive
C. reactive, average
D. apparent, average
Answer: A
Clarification: The power factor is the ratio of average power to the apparent power. Power factor =(average power)/(apparent power). Power factor is also defined as the factor with which the volt amperes are to be multiplied to get true power in the circuit.

11. The power factor is called leading power factor in case of ____ circuits.
A. LC
B. RC
C. RL
D. RLC
Answer: B
Clarification: The power factor is called leading power factor in case of RC circuits and not in RLC circuits and RL circuits and LC circuits.

12. The term lagging power factor is used in which circuits?
A. RLC
B. RC
C. RL
D. LC
Answer: C
Clarification: The term lagging power factor is used in RL circuits and not in RLC circuits and RC circuits and LC circuits.

To practice all areas of Network Theory for Interviews,

250+ TOP MCQs on Inter Connection of Three-Phase Sources and Loads and Answers

Network Theory Quiz on “Inter Connection of Three-Phase Sources and Loads”.

1. In a three phase alternator, there are __________ independent phase windings or coils.
A. 1
B. 2
C. 3
D. 4

Answer: C
Clarification: In a three phase alternator, there are 3 independent phase windings or coils. So, 3 independent phase windings or coils. The end connections of the three sets of the coils may be brought out of the machine to form three separate single phase sources to feed three individual circuits.

2. Each coil in three phase alternator has ________________ number of terminals.
A. 2
B. 4
C. 6
D. 8

Answer: A
Clarification: Each coil in three phase alternator has 2 number of terminals, viz. start and finish. So, 2 number of terminals. the coils are inter connected to form a wye or delta connected three phase system to achieve economy and reduce the number of conductors and thereby the complexity of the circuit.

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

Answer: A
Clarification: In wye or star connection, similar ends of the three phases are joined together within the alternator. The common terminal so formed is referred to as the neutral point or neutral terminal.

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

Answer: D
Clarification: In a three phase four wire star connected system, the terminals R, Y and B are called the line terminals of the source. The voltage between line and neutral point is called phase voltage. And the voltage between line and line is called line voltage.

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

Answer: C
Clarification: The voltage between line and line is called line voltage. And the voltage between line and neutral point is called phase voltage. The currents flowing through the phases are called the phase currents, while those flowing in the lines are called the line currents.

6. Figure below represents three phases of an alternator. The phase voltage for the star connection among the options given below is?
A. VRY
B. VRN
C. VYB
D. VBR

Answer: B
Clarification: If the neutral wire is not available for external connection, the system is called a three phase,three wire star connected system. Phase voltage = VRN. And VRY, VYB and VBR are not phase voltages.

7. In the figure shown below, what will be the line voltage?
A. VBR
B. VBN
C. VRN
D. VYN

Answer: A

8. In the Delta or Mesh connection, there will be __________ number of common terminals.
A. 1
B. 2
C. 3
D. 0

Answer: D
Clarification: The three line conductors are taken from the three junctions of the mesh or delta connection to feed the three phase load. This constitutes a three phase, three wire, delta connected system. In the Delta or Mesh connection, there will be zero number of common terminals. Number of common terminals = 0.

9. The relation between line voltage and phase voltage in Delta or Mesh connection is?
A. Vphase > Vline
B. Vphase < Vline
C. Vphase = Vline
D. Vphase >= Vline

Answer: C
Clarification: When the sources are connected in delta, loads can be connected only across the three line terminal. The relation between line voltage and phase voltage in Delta or Mesh connection is Vphase = Vline.

10. Which of the following voltage is a phase voltage in the delta connection?
A. VRN
B. VBR
C. VYN
D. VBN

Answer: B

250+ TOP MCQs on Circuit Elements in the S-Domain and Answers

Network Theory Multiple Choice Questions on “Circuit Elements in the S-Domain”.

1. The resistance element __________ while going from the time domain to frequency domain.
A. does not change
B. increases
C. decreases
D. increases exponentially

Answer: A
Clarification: The s-domain equivalent circuit of a resistor is simply resistance of R ohms that carries a current I ampere seconds and has a terminal voltage V volts-seconds. The resistance element does not change while going from the time domain to the frequency domain.

2. The relation between current and voltage in the case of inductor is?
A. v=Ldt/di
B. v=Ldi/dt
C. v=dt/di
D. v=di/dt

Answer: B
Clarification: Consider an inductor with an initial current Io. The time domain relation between current and voltage is v=Ldi/dt.

3. The s-domain equivalent of the inductor reduces to an inductor with impedance?
A. L
B. sL
C. s2L
D. s3L

Answer: B
Clarification: If the initial energy stored in the inductor is zero, the equivalent circuit of the inductor reduces to an inductor with impedance sL ohms.

4. The voltage and current in a capacitor are related as?
A. i=Cdt/dv
B. v=Cdv/dt
C. i=Cdv/dt
D. v=Cdt/dv

Answer: C
Clarification: Consider an initially charged capacitor and the initial voltage on the capacitor is Vo. The voltage current relation in the time domain is i=Cdv/dt.

5. The s-domain equivalent of the capacitor reduces to a capacitor with impedance?
A. sC
B. C
C. 1/C
D. 1/sC

Answer: D
Clarification: The s-domain equivalent of the capacitor can be derived for the charged capacitor and it reduces to an capacitor with impedance 1/sC.

6. From the circuit shown below, find the value of current in the loop.
A. (V/R)/(s+1/RC.
B. (V/C./(s+1/R)
C. (V/C./(s+1/RC.
D. (V/R)/(s+1/R)

Answer: A
Clarification: Applying Kirchhoff’s law around the loop, we have V/s=1/sC I+RI. Solving above equation yields I=CV/(RCS+1)=(V/R)/(s+1/RC..

7. After taking the inverse transform of current in the circuit shown below, the value of current is?

A. i=(V/C.e-t/R
B. i=(V/C.e-t/RC
C. i=(V/R)e-t/RC
D. i=(V/R)e-t/R

Answer: C
Clarification: We had assumed the capacitor is initially charged to Vo volts. By taking the inverse transform of the current, we get i=(V/R) e-t/RC.

8. The voltage across the resistor in the circuit shown below is?

A. Vet/R
B. Ve-t/RC
C. Ve-t/R
D. Vet/RC

Answer: B
Clarification: We can determine the voltage v by simply applying the ohm’s law from the circuit. And applying the Ohm’s law from the circuit v = Ri = Ve-t/RC.

9. The voltage across the resistor in the parallel circuit shown is?

A. V/(s-1/R)
B. V/(s-1/RC.
C. V/(s+1/RC.
D. V/(s+1/C.

Answer: C
Clarification: The given circuit is converted to parallel equivalent circuit. By taking the node equation, we get v/R+sCv=CV. Solving the above equation, v=V/(s+1/RC..

10. Taking the inverse transform of the voltage across the resistor in the circuit shown below is?

A. Ve-t/τ
B. Vet/τ
C. Ve
D. Ve-tτ

Answer: A
Clarification: By taking the inverse transform, we get v=Ve-t/RC=Ve-t/τ, where τ is the time constant and τ = RC. And v is the voltage across the resistor.

250+ TOP MCQs on Hybrid (h) Parameter and Answers

Network Theory Multiple Choice Questions on “Hybrid (h) Parameter”.

1. For the circuit given below, the value of the hybrid parameter h11 is ___________

A. 15 Ω
B. 20 Ω
C. 30 Ω
D. 25 Ω

Answer: A
Clarification: Hybrid parameter h11 is given by, h11 = (frac{V_1}{I_1}), when V2=0.
Therefore short circuiting the terminal Y-Y’, we get,
V1 = I1 ((10||10) + 10)
= I1 (left(left(frac{10×10}{10+10}right)+10right))
= 15I1
∴ (frac{V_1}{I_1}) = 15.
Hence h11 = 15 Ω.

2. For the circuit given below, the value of the hybrid parameter h21 is ___________

A. 0.6 Ω
B. 0.5 Ω
C. 0.3 Ω
D. 0.2 Ω

Answer: B
Clarification: Hybrid parameter h21 is given by, h21 = (frac{I_2}{I_1}), when V2=0.
Therefore short circuiting the terminal Y-Y’, and applying Kirchhoff’s law, we get,
-10 I2 – (I2 – I1)10 = 0
Or, -I2 = I2 – I1
Or, -2I2 = -I1
∴ (frac{I_2}{I_1} = frac{1}{2})
Hence h21 = 0.5 Ω.

3. For the circuit given below, the value of the hybrid parameter h12 is ___________

A. 6 Ω
B. 5 Ω
C. 1 Ω
D. 2 Ω

Answer: C
Clarification: Hybrid parameter h12 is given by, h12 = (frac{V_1}{V_2}), when I1 = 0.
Therefore short circuiting the terminal X-X’ we get,
V1 = IA × 10
IA = (frac{I_2}{2})
V2 = IB × 10
IB = (frac{I_2}{2})
From the above 4 equations, we get,
∴ (frac{V_1}{V_2} = frac{I_2×10}{I_2×10}) = 1
Hence h12 = 1 Ω.

4. For the circuit given below, the value of the hybrid parameter h22 is ___________

A. 0.2 Ω
B. 0.5 Ω
C. 0.1 Ω
D. 0.3 Ω

Answer: A
Clarification: Hybrid parameter h22 is given by, h22 = (frac{I_2}{V_2}), when I1 = 0.
Therefore short circuiting the terminal X-X’ we get,
V1 = IA × 10
IA = (frac{I_2}{2})
V2 = IB × 10
IB = (frac{I_2}{2})
From the above 4 equations, we get,
∴ (frac{I_2}{V_2} = frac{I_2×2}{I_2×10}) = 0.2
Hence h22 = 0.2 Ω.

5. In the circuit given below, the value of the hybrid parameter h11 is _________

A. 10 Ω
B. 7.5 Ω
C. 5 Ω
D. 2.5 Ω

Answer: B
Clarification: Hybrid parameter h11 is given by, h11 = (frac{V_1}{I_1}), when V2 = 0.
Therefore short circuiting the terminal Y-Y’, we get,
V1 = I1 ((5 || 5) + 5)
= I1 (left(left(frac{5×5}{5+5}right)+5right))
= 7.5I1
∴ (frac{V_1}{I_1}) = 7.5
Hence h11 = 7.5 Ω.

6. In the circuit given below, the value of the hybrid parameter h21 is _________

A. 10 Ω
B. 0.5 Ω
C. 5 Ω
D. 2.5 Ω

Answer: B
Clarification: Hybrid parameter h21 is given by, h21 = (frac{I_2}{I_1}), when V2 = 0.
Therefore short circuiting the terminal Y-Y’, and applying Kirchhoff’s law, we get,
-5 I2 – (I2 – I1)5 = 0
Or, -I2 = I2 – I1
Or, -2I2 = -I1
∴ (frac{I_2}{I_1} = frac{1}{2})
Hence h21 = 0.5 Ω.

7. For the circuit given below, the value of the hybrid parameter h12 is ___________

A. 6 Ω
B. 5 Ω
C. 1 Ω
D. 2 Ω

Answer: C
Clarification: Hybrid parameter h12 is given by, h12 = (frac{V_1}{V_2}), when I1 = 0.
Therefore short circuiting the terminal X-X’ we get,
V1 = IA × 5
V2 = IA × 5
From the above equations, we get,
∴ (frac{V_1}{V_2} = frac{I_A×10}{I_A×10}) = 1
Hence h12 = 1 Ω.

8. For the circuit given below, the value of the hybrid parameter h22 is ___________

A. 0.2 Ω
B. 0.5 Ω
C. 0.1 Ω
D. 0.3 Ω

Answer: A
Clarification: Hybrid parameter h22 is given by, h22 = (frac{I_2}{V_2}), when I1 = 0.
Therefore short circuiting the terminal X-X’ we get,
V1 = IA × 5
V2 = IA × 5
IA = I2
From the above equations, we get,
∴ (frac{I_2}{V_2} = frac{I_2}{I_2×5}) = 0.2
Hence h22 = 0.2 Ω.

9. In two-port networks the parameter h11 is called _________
A. Short circuit input impedance
B. Short circuit current gain
C. Open circuit reverse voltage gain
D. Open circuit output admittance

Answer: A
Clarification: We know that, h11 = (frac{V_1}{I_1}), when V2 = 0.
Since the second output terminal is short circuited when the ratio of the two voltages is measured, therefore the parameter h11 is called as Short circuit input impedance.

10. In two-port networks the parameter h21 is called _________
A. Short circuit input impedance
B. Short circuit current gain
C. Open circuit reverse voltage gain
D. Open circuit output admittance

Answer: B
Clarification: We know that, h21 = (frac{I_2}{I_1}), when V2 = 0.
Since the second output terminal is short circuited when the ratio of the two currents is measured, therefore the parameter h21 is called Short circuit current gain.

11. In two-port networks the parameter h12 is called _________
A. Short circuit input impedance
B. Short circuit current gain
C. Open circuit reverse voltage gain
D. Open circuit output admittance

Answer: C
Clarification: We know that, h21 = (frac{V_1}{V_2}), when I1 = 0.
Since the current in the first loop is 0 when the ratio of the two voltages is measured, therefore the parameter h12 is called as Open circuit reverse voltage gain.

12. In two-port networks the parameter h22 is called _________
A. Short circuit input impedance
B. Short circuit current gain
C. Open circuit reverse voltage gain
D. Open circuit output admittance

Answer: D
Clarification: We know that, h22 = (frac{I_2}{V_2}), when I1 = 0.
Since the current in the first loop is 0 when the ratio of the current and voltage in the second loop is measured, therefore the parameter h22 is called as Open circuit output admittance.

13. For a T-network if the Short circuit admittance parameters are given as y11, y21, y12, y22, then y11 in terms of Hybrid parameters can be expressed as ________
A. y11 = (left(- frac{h_{21} h_{12}}{h_{11}} + h_{22}right))
B. y11 = (frac{h_{21}}{h_{11}})
C. y11 = –(frac{h_{12}}{h_{11}})
D. y11 = (frac{1}{h_{11}} )

Answer: D
Clarification: We know that the short circuit admittance parameters can be expressed in terms of voltages and currents as,
I1 = y11 V1 + y12 V2 ……… (1)
I2 = y21 V1 + y22 V2 ………. (2)
And the Hybrid parameters can be expressed in terms of voltages and currents as,
V1 = h11 I1 + h12 V2 ………. (3)
I2 = h21 I1 + h22 V2 ……….. (4)
Now, (3) and (4) can be rewritten as,
I1 = (frac{V_1}{h_{11}} – frac{h_{12} V_2}{h_{11}}) ………. (5)
And I2 = (frac{h_{21} V_1}{h_{11}} + left(- frac{h_{21} h_{12}}{h_{11}} + h_{22}right) V_2) ………. (6)
∴ Comparing (1), (2) and (5), (6), we get,
y11 = (frac{1}{h_{11}} )
y12 = –(frac{h_{12}}{h_{11}})
y21 = (frac{h_{21}}{h_{11}})
y22 = (left(- frac{h_{21} h_{12}}{h_{11}} + h_{22}right)).

14. For a T-network if the Short circuit admittance parameters are given as y11, y21, y12, y22, then y12 in terms of Hybrid parameters can be expressed as ________
A. y12 = (left(- frac{h_{21} h_{12}}{h_{11}} + h_{22}right))
B. y12 = (frac{h_{21}}{h_{11}})
C. y12 = –(frac{h_{12}}{h_{11}})
D. y12 = (frac{1}{h_{11}} )

Answer: C
Clarification: We know that the short circuit admittance parameters can be expressed in terms of voltages and currents as,
I1 = y11 V1 + y12 V2 ……… (1)
I2 = y21 V1 + y22 V2 ………. (2)
And the Hybrid parameters can be expressed in terms of voltages and currents as,
V1 = h11 I1 + h12 V2 ………. (3)
I2 = h21 I1 + h22 V2 ……….. (4)
Now, (3) and (4) can be rewritten as,
I1 = (frac{V_1}{h_{11}} – frac{h_{12} V_2}{h_{11}}) ………. (5)
And I2 = (frac{h_{21} V_1}{h_{11}} + left(- frac{h_{21} h_{12}}{h_{11}} + h_{22}right) V_2) ………. (6)
∴ Comparing (1), (2) and (5), (6), we get,
y11 = (frac{1}{h_{11}} )
y12 = –(frac{h_{12}}{h_{11}})
y21 = (frac{h_{21}}{h_{11}})
y22 = (left(- frac{h_{21} h_{12}}{h_{11}} + h_{22}right)).

15. For a T-network if the Short circuit admittance parameters are given as y11, y21, y12, y22, then y22 in terms of Hybrid parameters can be expressed as ________
A. y22 = (left(- frac{h_{21} h_{12}}{h_{11}} + h_{22}right))
B. y22 = (frac{h_{21}}{h_{11}})
C. y22 = –(frac{h_{12}}{h_{11}})
D. y22 = (frac{1}{h_{11}} )

Answer: A
Clarification: We know that the short circuit admittance parameters can be expressed in terms of voltages and currents as,
I1 = y11 V1 + y12 V2 ……… (1)
I2 = y21 V1 + y22 V2 ………. (2)
And the Hybrid parameters can be expressed in terms of voltages and currents as,
V1 = h11 I1 + h12 V2 ………. (3)
I2 = h21 I1 + h22 V2 ……….. (4)
Now, (3) and (4) can be rewritten as,
I1 = (frac{V_1}{h_{11}} – frac{h_{12} V_2}{h_{11}}) ………. (5)
And I2 = (frac{h_{21} V_1}{h_{11}} + left(- frac{h_{21} h_{12}}{h_{11}} + h_{22}right) V_2) ………. (6)
∴ Comparing (1), (2) and (5), (6), we get,
y11 = (frac{1}{h_{11}} )
y12 = –(frac{h_{12}}{h_{11}})
y21 = (frac{h_{21}}{h_{11}})
y22 = (left(- frac{h_{21} h_{12}}{h_{11}} + h_{22}right)).

250+ TOP MCQs on Kirchhoff’s Voltage Law and Answers

Network Theory Multiple Choice Questions on “Kirchhoff’s Voltage Law”.

1. Kirchhoff’s voltage law is based on principle of conservation of ___________
A. energy
B. momentum
C. mass
D. charge
Answer: A
Clarification: KVL is based on the law of conservation of energy.

2. In a circuit with more number of loops, which law can be best suited for the analysis?
A. KCL
B. Ohm’s law
C. KVL
D. None of the mentioned
Answer: C
Clarification: KVL can be best suited for circuits with more number of loops.

3. Mathematically, Kirchhoff’s Voltage law can be _____________
A. ∑_(k=0)n(V) = 0
B. V2∑_(k=0)n(V) = 0
C. V∑_(k=0)n(V) = 0
D. None of the mentioned
Answer: A
Clarification: According to KVL, the sum of all voltages of branches in a closed loop is zero.

To practice all areas of Network Theory,

250+ TOP MCQs on Millman’s Theorem and Answers

Network Theory Multiple Choice Questions on “Millman’s Theorem”.

1. According to Millman’s Theorem, if there are n voltage sources with n internal resistances respectively, are in parallel, then these sources are replaced by?
A. single current source I’ in series with R’
B. single voltage source V’ in series with R’
C. single current source I’ in parallel to R’
D. single voltage source V’ in parallel to R’
Answer: B
Clarification: Millman’s Theorem states that if there are voltage sources V1, V2,…… Vn with internal resistances R1, R2,…..Rn, respectively, are in parallel, then these sources are replaced by single voltage source V’ in series with R’.

2. According to Millman’s Theorem, if there are n voltage sources with n internal resistances respectively, are in parallel, then the value of equivalent voltage source is?
A. V=(V1G1+V2G2+⋯.+VnGn)
B. V=((V1G1+V2G2+⋯.+VnGn))/((1/G1+1/G2+⋯1/Gn))
C. V=((V1G1+V2G2+⋯.+VnGn))/(G1+G2+⋯Gn)
D. V=((V1/G1+V2/G2+⋯.+Vn/Gn))/( G1+G2+⋯Gn)
Answer: C
Clarification: The value of equivalent voltage source is V= ((V1G1+V2G2+⋯.+VnGn))/(G1+G2+⋯Gn).

3. According to Millman’s Theorem, if there are n voltage sources with n internal resistances respectively, are in parallel, then the value of equivalent resistance is?
A. R’=G1+G2+⋯Gn
B. R’=1/G1+1/G2+⋯1/Gn
C. R’=1/((G1+G2+⋯Gn))
D. R’=1/(1/G1+1/G2+⋯1/Gn)
Answer: C
Clarification: Let the equivalent resistance is R’. The value of equivalent resistance is R’=1/((G1+G2+⋯Gn)).

4. According to Millman’s Theorem, if there are n current sources with n internal conductances respectively, are in series, then these sources are replaced by?
A. single voltage source V’ in parallel with G’
B. single current source I’ in series with G’
C. single current source I’ in parallel with G’
D. single voltage source V’ in series with G’
Answer: C
Clarification: Millman’s Theorem states that if there are current sources I1,I2,…… In with internal conductances G1,G2,…..Gn, respectively, are in series, then these sources are replaced by single current source I’ in parallel with G’.

5. According to Millman’s Theorem, if there are n current sources with n internal conductances respectively, are in series, then the value of equivalent current source is?
A. I=((I1R1+I2R2+⋯.+InRn))/(R1+R2+⋯Rn)
B. I’=I1R1+I2R2+⋯.+InRn
C. I’=((I1/R1+I2/R2+⋯.+In/Rn))/(R1+R2+⋯Rn)
D. I’=I1/R1+I2/R2+⋯.+In/Rn
Answer: A
Clarification: The value of equivalent current source is I=((I1R1+I2R2+⋯.+InRn))/(R1+R2+⋯Rn).

6. According to Millman’s Theorem, if there are n current sources with n internal conductances respectively, are in series, then the value of equivalent conductance is?
A. G’=R1+R2+⋯Rn
B. G’=1/(1/R1+1/R2+⋯1/Rn)
C. G’=1/((R1+R2+⋯Rn))
D. G’=1/R1+1/R2+⋯1/Rn
Answer: C
Clarification: Let the equivalent conductance is G’. The value of equivalent conductance is G’=1/((R1+R2+⋯Rn)).

7. Calculate the current through 3Ω resistor in the circuit shown below.
millmans-theorem-q7″>network-theory-questions-answers-millmans-theorem-q7
A. 1
B. 2
C. 3
D. 4
Answer: C
Clarification: Applying Nodal analysis the voltage V is given by (10-V)/2+(20-V)/5=V/3. V=8.7V. Now the current through 3Ω resistor in the circuit is I = V/3 = 8.7/3 = 2.9A ≅ 3A.

8. Find the current through 3Ω resistor in the circuit shown below using Millman’s Theorem.
millmans-theorem-q7″>millmans-theorem-q7″ alt=”network-theory-questions-answers-millmans-theorem-q7″ width=”226″ height=”106″ class=”alignnone size-full wp-image-170305″>
A. 4
B. 3
C. 2
D. 1
Answer: B
Clarification: V=((V1G1+V2G2))/(G1+G2)=(10(1/2)+20(1/5))/(1/2+1/5)=12.86V. R’=1/((G1+G2))=1/(1/2+1/5)=1.43Ω. Current through 3Ω resistor=I=12.86/(3+1.43)=2.9A≅3A.

9. Consider the circuit shown below. Find the current through 4Ω resistor.
millmans-theorem-q9″>millmans-theorem-q9″ alt=”network-theory-questions-answers-millmans-theorem-q9″ width=”223″ height=”107″ class=”alignnone size-full wp-image-170307″>
A. 2
B. 1.5
C. 1
D. 0.5
Answer: B
Clarification: Applying Nodal analysis the voltage V is given by (5-V)/1+(10-V)/3=V/4. V=6V. The current through 4Ω resistor I = V/4 = 6/4 = 1.5A.

10. In the following circuit. Find the current through 4Ω resistor using Millman’s Theorem.
millmans-theorem-q9″>millmans-theorem-q9″ alt=”network-theory-questions-answers-millmans-theorem-q9″ width=”223″ height=”107″ class=”alignnone size-full wp-image-170307″>
A. 0.5
B. 1
C. 1.5
D. 2
Answer: C
Clarification: V=((V1G1+V2G2))/(G1+G2)=(5(1/1)+10(1/3))/(1/1+1/3)=6.25V. R’=1/((G1+G2))=1/(1/1+1/3)=0.75Ω. I=6.25/(4+0.75)=1.5A.