Network Theorems MCQs

Practice Network Theorems MCQs with four options, answers and explanations for focused Electronics & Telecommunication Engineering revision.

Question 1

Network TheoryNetwork Theorems

When deactivating an independent ideal voltage source for superposition analysis, it is replaced by?

AAn open circuit
BA short circuit
CA capacitor
DA current source

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Correct Answer: B. A short circuit

Explanation: Setting an ideal independent voltage source to zero volts makes it equivalent to a short circuit.

Reference: Standard network theory: network theorems

Question 2

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When deactivating an independent ideal current source for superposition analysis, it is replaced by?

AA short circuit
BAn open circuit
CA voltage source
DAn inductor

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Correct Answer: B. An open circuit

Explanation: Setting an ideal independent current source to zero amperes makes it equivalent to an open circuit.

Reference: Standard network theory: network theorems

Question 3

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

ALinear networks
BOnly nonlinear networks
COnly magnetic circuits
DOnly circuits with one source

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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 4

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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

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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 5

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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

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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

Question 6

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For equivalent Thevenin and Norton circuits, the relation between Vth, IN and Rth is?

AVth = IN/Rth
BVth = IN Rth
CVth = Rth/IN
DVth = IN + Rth

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Correct Answer: B. Vth = IN Rth

Explanation: The equivalent forms satisfy Vth = IN Rth, with Rth equal to RN.

Reference: Standard network theory: network theorems

Question 7

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A Thevenin equivalent has Vth = 20 V and Rth = 5 ohm. The Norton current is?

A2 A
B4 A
C5 A
D100 A

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Correct Answer: B. 4 A

Explanation: IN = Vth/Rth = 20/5 = 4 A.

Reference: Standard network theory: network theorems

Question 8

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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

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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

Question 9

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If a test voltage of 10 V applied to a two-terminal network causes a current of 2 A to enter the network, its equivalent resistance is?

A0.2 ohm
B2 ohm
C5 ohm
D20 ohm

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Correct Answer: C. 5 ohm

Explanation: Req = Vtest/Itest = 10/2 = 5 ohm.

Reference: Standard network theory: network theorems

Question 10

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The reciprocity theorem is applicable to a linear bilateral network containing a single independent source when comparing?

AInterchanged excitation and response locations
BOnly total resistance with all sources removed
COnly nonlinear diode currents
DOnly transient initial conditions

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Correct Answer: A. Interchanged excitation and response locations

Explanation: Reciprocity states, under its applicable conditions, that interchanging the location of excitation and measured response gives the same transfer relationship.

Reference: Standard network theory: reciprocity theorem

Question 11

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Millman’s theorem is particularly convenient for finding the voltage at a node connected to several parallel branches containing?

AVoltage sources with series impedances
BOnly ideal inductors in series
COnly dependent current sources with no impedance
DA single resistor only

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Correct Answer: A. Voltage sources with series impedances

Explanation: Millman's theorem combines multiple parallel source-impedance branches into a direct weighted expression for the common node voltage.

Reference: Standard network theory: Millman theorem

Question 12

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Two parallel branches connect a node to ground. Branch 1 has a 10 V source in series with 5 ohm and branch 2 has a 5 V source in series with 5 ohm, with both source polarities tending to make the node positive. By Millman’s theorem, the node voltage is?

A2.5 V
B5 V
C7.5 V
D15 V

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Correct Answer: C. 7.5 V

Explanation: V=(10/5+5/5)/(1/5+1/5)=3/0.4=7.5 V.

Reference: Standard network theory: Millman theorem numerical

Question 13

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Tellegen’s theorem is fundamentally based on conservation of?

APower in a network satisfying KCL and KVL
BResistance only
CFrequency only
DMagnetic flux only

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Correct Answer: A. Power in a network satisfying KCL and KVL

Explanation: Tellegen's theorem states that the algebraic sum of instantaneous branch powers is zero for networks whose branch voltages and currents satisfy KVL and KCL.

Reference: Standard network theory: Tellegen theorem

Question 14

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For a linear circuit containing several independent sources, superposition is applied to calculate?

AVoltages and currents, not power directly
BPower directly by adding individual source powers at an element
CEquivalent resistance only
DFrequency only

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Correct Answer: A. Voltages and currents, not power directly

Explanation: Superposition applies to linear response quantities such as voltage and current. Power is nonlinear in voltage/current and cannot generally be superposed directly.

Reference: Standard network theory: superposition limitation

Question 15

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While applying superposition, an independent ideal voltage source that is not being considered is replaced by?

AAn open circuit
BA short circuit
CIts internal power rating
DA dependent source

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Correct Answer: B. A short circuit

Explanation: Setting an ideal independent voltage source to zero volts makes it a short circuit.

Reference: Standard network theory: superposition voltage-source suppression

Question 16

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While applying superposition, an independent ideal current source that is not being considered is replaced by?

AA short circuit
BAn open circuit
CA voltage source of equal value
DA resistor of 1 ohm

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Correct Answer: B. An open circuit

Explanation: Setting an ideal independent current source to zero amperes makes it an open circuit.

Reference: Standard network theory: superposition current-source suppression

Question 17

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The substitution theorem permits a branch of a network to be replaced by another element or source provided the replacement maintains the same?

ABranch voltage and current
BTotal number of nodes only
COperating frequency only
DPower factor of every other branch only

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Correct Answer: A. Branch voltage and current

Explanation: At a specified operating condition, substitution is valid when the replacement preserves the original branch terminal voltage and current.

Reference: Standard network theory: substitution theorem

Question 18

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The compensation theorem is useful for determining changes in network currents and voltages caused by a change in?

AA branch impedance
BThe number of graph nodes only
CSource frequency with every impedance fixed
DReference-node labeling

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Correct Answer: A. A branch impedance

Explanation: The compensation theorem evaluates incremental response when a branch impedance changes in a linear bilateral network.

Reference: Standard network theory: compensation theorem

Question 19

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If a branch carrying current I has its impedance increased by Delta Z, the compensating source magnitude used in the compensation theorem is proportional to?

AI/Delta Z
BI Delta Z
CI squared divided by Delta Z
DDelta Z/I squared

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Correct Answer: B. I Delta Z

Explanation: The compensating voltage magnitude is I Delta Z, with polarity chosen according to the theorem's replacement convention.

Reference: Standard network theory: compensation theorem relation