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Network Theory MCQs

Practice Network Theory MCQs from fundamental concepts through intermediate, advanced and application-oriented questions. Each page contains up to 100 questions with answers and explanations where available.

Question 4
Network TheoryKirchhoff Laws

Kirchhoff’s Current Law states that at any node?

  • AThe algebraic sum of currents is zero
  • BThe algebraic sum of voltages is always one
  • CPower is always zero
  • DResistance is always maximum
Report an error
Correct Answer: A. The algebraic sum of currents is zero
Explanation: KCL follows conservation of charge: the algebraic sum of currents entering and leaving a node is zero.
Reference: Standard network theory: kirchhoff laws
Question 5
Network TheoryKirchhoff Laws

Kirchhoff’s Voltage Law states that around any closed loop?

  • AThe algebraic sum of currents is zero
  • BThe algebraic sum of voltages is zero
  • CAll resistances are equal
  • DAll branch currents are equal
Report an error
Correct Answer: B. The algebraic sum of voltages is zero
Explanation: KVL follows conservation of energy: the algebraic sum of voltage rises and drops around a closed loop is zero.
Reference: Standard network theory: kirchhoff laws
Question 10
Network TheoryCircuit Fundamentals

According to Ohm’s law, the voltage across a resistor is equal to?

  • ACurrent divided by resistance
  • BCurrent multiplied by resistance
  • CResistance divided by current
  • DPower multiplied by current
Report an error
Correct Answer: B. Current multiplied by resistance
Explanation: Ohm's law is V = IR, where V is voltage, I is current and R is resistance.
Reference: Standard network theory: circuit fundamentals
Question 18
Network TheoryTransient Analysis

In DC steady state after a long time, an ideal capacitor behaves as a?

  • AShort circuit
  • BOpen circuit
  • CVoltage source of zero resistance in every case
  • DCurrent source
Report an error
Correct Answer: B. Open circuit
Explanation: For constant DC voltage, capacitor current i = C dv/dt becomes zero, so an ideal capacitor behaves as an open circuit in steady state.
Reference: Standard network theory: transient analysis
Question 21
Network TheoryNetwork Theorems

The superposition theorem is directly applicable to which type of network?

  • ALinear networks
  • BOnly nonlinear networks
  • COnly magnetic circuits
  • DOnly circuits with one source
Report an error
Correct Answer: A. Linear networks
Explanation: Superposition applies to linear circuits containing multiple independent sources; responses from individual sources are summed.
Reference: Standard network theory: network theorems
Question 22
Network TheoryNetwork Theorems

Thevenin’s theorem replaces a linear two-terminal network by?

  • AA current source in series with resistance
  • BA voltage source in series with resistance
  • CA voltage source in parallel with zero resistance only
  • DA capacitor and inductor only
Report an error
Correct Answer: B. A voltage source in series with resistance
Explanation: The Thevenin equivalent consists of an ideal voltage source Vth in series with an equivalent resistance or impedance.
Reference: Standard network theory: network theorems
Question 23
Network TheoryNetwork Theorems

Norton’s theorem replaces a linear two-terminal network by?

  • AA current source in parallel with resistance
  • BA voltage source in series with resistance
  • COnly a resistance
  • DOnly an inductor
Report an error
Correct Answer: A. A current source in parallel with resistance
Explanation: The Norton equivalent consists of an ideal current source IN in parallel with an equivalent resistance or impedance.
Reference: Standard network theory: network theorems
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Question 27
Network TheoryNodal Analysis

In nodal analysis, the principal unknown quantities are usually?

  • ABranch powers
  • BNode voltages with respect to a reference node
  • CLoop charges
  • DOnly source currents
Report an error
Correct Answer: B. Node voltages with respect to a reference node
Explanation: Nodal analysis applies KCL to determine node voltages relative to a chosen reference or ground node.
Reference: Standard network theory: nodal analysis
Question 35
Network TheoryAC Circuit Analysis

Admittance is defined as?

  • AThe reciprocal of impedance
  • BThe square of impedance
  • CResistance plus reactance only
  • DVoltage divided by power
Report an error
Correct Answer: A. The reciprocal of impedance
Explanation: Admittance Y = 1/Z and is measured in siemens.
Reference: Standard network theory: ac circuit analysis
Question 37
Network TheoryAC Circuit Analysis

The reciprocal of resistance is called?

  • AReactance
  • BConductance
  • CSusceptance
  • DInductance
Report an error
Correct Answer: B. Conductance
Explanation: Conductance G = 1/R and is measured in siemens.
Reference: Standard network theory: ac circuit analysis
Question 38
Network TheoryMesh Analysis

In mesh analysis, the principal unknown quantities are usually?

  • ANode voltages
  • BMesh currents
  • CCapacitances only
  • DSource powers only
Report an error
Correct Answer: B. Mesh currents
Explanation: Mesh analysis assigns a current to each independent mesh and uses KVL equations to solve for those currents.
Reference: Standard network theory: mesh analysis
Question 39
Network TheoryAC Circuit Analysis

In a purely inductive AC circuit, current ideally?

  • ALeads voltage by 90 degrees
  • BLags voltage by 90 degrees
  • CIs in phase with voltage
  • DLags voltage by 180 degrees
Report an error
Correct Answer: B. Lags voltage by 90 degrees
Explanation: For an ideal inductor, voltage leads current by 90 degrees; equivalently, current lags voltage by 90 degrees.
Reference: Standard network theory: ac circuit analysis
Question 40
Network TheoryMesh Analysis

Two adjacent meshes have currents I1 and I2 flowing through a common resistor R in opposite directions. The voltage drop associated with mesh I1 across the common resistor is?

  • AR(I1+I2)
  • BR(I1-I2)
  • CR/I1
  • DR(I2-I1) only regardless of reference
Report an error
Correct Answer: B. R(I1-I2)
Explanation: With the mesh currents opposing each other in the shared branch, the branch current referenced in I1's direction is I1-I2, so the drop is R(I1-I2).
Reference: Standard network theory: mesh analysis
Question 41
Network TheoryAC Circuit Analysis

In a purely capacitive AC circuit, current ideally?

  • ALags voltage by 90 degrees
  • BLeads voltage by 90 degrees
  • CIs in phase with voltage
  • DLeads voltage by 180 degrees
Report an error
Correct Answer: B. Leads voltage by 90 degrees
Explanation: For an ideal capacitor, current leads voltage by 90 degrees.
Reference: Standard network theory: ac circuit analysis
Question 42
Network TheorySource Transformation

A 12 V ideal voltage source in series with a 3 ohm resistor is source-transformed into?

  • AA 4 A current source in parallel with 3 ohm
  • BA 36 A current source in parallel with 3 ohm
  • CA 4 A current source in series with 3 ohm
  • DA 3 A current source in parallel with 4 ohm
Report an error
Correct Answer: A. A 4 A current source in parallel with 3 ohm
Explanation: The equivalent current is I = V/R = 12/3 = 4 A, and the same 3 ohm resistance is placed in parallel.
Reference: Standard network theory: source transformation
Question 44
Network TheorySource Transformation

A 5 A ideal current source in parallel with a 2 ohm resistor is equivalent to?

  • AA 2.5 V source in series with 2 ohm
  • BA 7 V source in series with 2 ohm
  • CA 10 V source in series with 2 ohm
  • DA 10 V source in parallel with 2 ohm
Report an error
Correct Answer: C. A 10 V source in series with 2 ohm
Explanation: The equivalent voltage is V = IR = 5×2 = 10 V, with the 2 ohm resistance in series.
Reference: Standard network theory: source transformation
Question 50
Network TheoryNetwork Theorems

When finding Thevenin resistance in a circuit containing dependent sources, dependent sources should generally be?

  • ATurned off like independent sources
  • BKept active
  • CAlways replaced by open circuits
  • DAlways replaced by short circuits
Report an error
Correct Answer: B. Kept active
Explanation: Dependent sources remain active because their values depend on circuit variables. A test source can be applied at the terminals to determine equivalent resistance.
Reference: Standard network theory: network theorems
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Question 55
Network TheorySecond-Order Circuits

A series RLC natural response is underdamped when?

  • Aalpha is less than omega0
  • Balpha equals omega0
  • Calpha is greater than omega0
  • DR is always zero only
Report an error
Correct Answer: A. alpha is less than omega0
Explanation: The second-order response is underdamped when alphaomega0.
Reference: Standard network theory: second-order circuits
Question 57
Network TheorySecond-Order Circuits

Critical damping in a second-order series RLC circuit occurs when?

  • Aalpha=0
  • Balpha=omega0
  • Calpha=2omega0
  • Domega0=0
Report an error
Correct Answer: B. alpha=omega0
Explanation: Critical damping occurs at the boundary between oscillatory and nonoscillatory responses, where alpha equals omega0.
Reference: Standard network theory: second-order circuits
Question 60
Network TheoryTransient Analysis

A first-order circuit is generally considered very close to its final steady-state value after approximately?

  • AOne time constant
  • BTwo time constants
  • CFive time constants
  • DTen milliseconds in every circuit
Report an error
Correct Answer: C. Five time constants
Explanation: After five time constants, a first-order response has completed more than 99% of its total transition and is commonly treated as essentially settled.
Reference: Standard network theory: transient analysis
Question 61
Network TheoryLaplace Transform

The Laplace transform of a unit step u(t) is?

  • A1
  • B1/s
  • Cs
  • D1/s^2
Report an error
Correct Answer: B. 1/s
Explanation: The unilateral or ordinary Laplace transform of the unit step for t>=0 is 1/s.
Reference: Standard network theory: laplace transform
Question 62
Network TheoryLaplace Transform

The Laplace transform of e^(-at)u(t) is?

  • A1/(s-a)
  • B1/(s+a)
  • Cs/(s+a)
  • Da/(s+a)
Report an error
Correct Answer: B. 1/(s+a)
Explanation: L{e^(-at)} = 1/(s+a), for the appropriate region of convergence.
Reference: Standard network theory: laplace transform
Question 63
Network TheoryLaplace Transform

The Laplace transform of sin(omega t)u(t) is?

  • As/(s^2+omega^2)
  • Bomega/(s^2+omega^2)
  • C1/(s+omega)
  • Domega/s^2
Report an error
Correct Answer: B. omega/(s^2+omega^2)
Explanation: The standard transform is L{sin(omega t)}=omega/(s^2+omega^2).
Reference: Standard network theory: laplace transform
Question 64
Network TheoryNetwork Functions

For a network with zero initial conditions, its transfer function H(s) is generally defined as?

  • AInput divided by output
  • BOutput transform divided by input transform
  • COutput plus input
  • DOnly the denominator polynomial
Report an error
Correct Answer: B. Output transform divided by input transform
Explanation: With zero initial conditions, H(s)=Y(s)/X(s), the ratio of output transform to input transform.
Reference: Standard network theory: network functions
Question 65
Network TheoryNetwork Functions

The poles of a network transfer function are the values of s that make its?

  • ANumerator zero
  • BDenominator zero
  • CInput resistance zero only
  • DOutput voltage always one
Report an error
Correct Answer: B. Denominator zero
Explanation: Poles are roots of the denominator polynomial of the transfer function after common factors have been removed.
Reference: Standard network theory: network functions
Question 66
Network TheoryNetwork Functions

The zeros of a transfer function are the values of s that make its?

  • ANumerator zero
  • BDenominator zero
  • CTime constant infinite only
  • DSupply voltage zero
Report an error
Correct Answer: A. Numerator zero
Explanation: Zeros are roots of the numerator polynomial after common factors have been removed.
Reference: Standard network theory: network functions
Question 67
Network TheoryNetwork Functions

For a stable continuous-time LTI network with a rational transfer function, all poles must lie where in the s-plane for asymptotic stability?

  • AStrictly in the left half-plane
  • BStrictly in the right half-plane
  • COnly on the positive real axis
  • DAnywhere with positive real part
Report an error
Correct Answer: A. Strictly in the left half-plane
Explanation: For a causal rational continuous-time system to be asymptotically stable, its poles must have negative real parts, i.e. lie strictly in the left half-plane.
Reference: Standard network theory: network functions
Question 73
Network TheoryTwo-Port Networks

The z-parameter equation for port 1 of a two-port network is?

  • AV1=z11 I1+z12 I2
  • BI1=z11 V1+z12 V2
  • CV1=z11 V1+z12 V2
  • DI1=z11 I1+z12 I2
Report an error
Correct Answer: A. V1=z11 I1+z12 I2
Explanation: By definition of impedance parameters, V1=z11I1+z12I2 and V2=z21I1+z22I2.
Reference: Standard network theory: two-port networks
Question 74
Network TheoryTwo-Port Networks

In ABCD or transmission parameters, which variables are commonly related for a two-port network?

  • AInput voltage/current to output voltage/current
  • BOnly the two port resistances
  • COnly input powers
  • DOnly output frequencies
Report an error
Correct Answer: A. Input voltage/current to output voltage/current
Explanation: ABCD parameters are particularly useful for cascaded networks because they relate input port variables to output port variables.
Reference: Standard network theory: two-port networks
Question 75
Network TheoryTwo-Port Networks

For cascaded two-port networks, the overall ABCD matrix is obtained by?

  • AAdding the individual ABCD matrices element by element
  • BMultiplying the individual ABCD matrices in cascade order
  • CTaking only the first matrix
  • DSubtracting all matrices
Report an error
Correct Answer: B. Multiplying the individual ABCD matrices in cascade order
Explanation: A key advantage of transmission parameters is that the ABCD matrix of a cascade is the ordered matrix product of the individual networks.
Reference: Standard network theory: two-port networks
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Question 77
Network TheoryAC Power

For a load with lagging power factor, power-factor correction is commonly achieved by connecting?

  • AA capacitor in parallel with the load
  • BAn additional resistor in series only
  • CA DC voltage source in parallel
  • DAn open circuit
Report an error
Correct Answer: A. A capacitor in parallel with the load
Explanation: A shunt capacitor supplies leading reactive power that offsets part of the load's lagging reactive power.
Reference: Standard network theory: ac power
Question 80
Network TheoryTwo-Port Networks

Two cascaded two-port networks have ABCD matrices M1 and M2. If M1 is followed by M2 from source to load, the overall transmission matrix is?

  • AM1+M2
  • BM2-M1
  • CM1M2
  • DM2/M1 element by element
Report an error
Correct Answer: C. M1M2
Explanation: For cascaded two-port networks, the overall ABCD matrix is the ordered product of the individual transmission matrices, M=M1M2 under the standard convention.
Reference: Standard network theory: two-port networks
Question 82
Network TheoryThree-Phase Circuits

The total real power in a balanced three-phase load is?

  • AVL IL cos(phi)
  • B√3 VL IL cos(phi)
  • C3 VL IL only
  • DVL IL sin(phi)
Report an error
Correct Answer: B. √3 VL IL cos(phi)
Explanation: Balanced three-phase real power is P=√3 VL IL cos(phi).
Reference: Standard network theory: three-phase circuits
Question 87
Network TheoryLaplace Transform

The inverse Laplace transform of 1/(s+4) is?

  • Ae^(-4t)u(t)
  • Be^(4t)u(t)
  • C4e^(-t)u(t)
  • Dsin(4t)u(t)
Report an error
Correct Answer: A. e^(-4t)u(t)
Explanation: The standard pair is 1/(s+a) ↔ e^(-at)u(t).
Reference: Standard network theory: laplace transform
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