Two-Port Networks MCQs

Practice Two-Port Networks MCQs with four options, answers and explanations for focused Electronics & Telecommunication Engineering revision.

Question 1

Network TheoryTwo-Port Networks

For a reciprocal two-port network described by z-parameters, which relation must hold?

Az11=z22 always
Bz12=z21
Cz11=0
Dz12=-z21

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Correct Answer: B. z12=z21

Explanation: A reciprocal two-port has equal transfer impedances: z12=z21.

Reference: Standard network theory: two-port networks

Question 2

Network TheoryTwo-Port Networks

For a symmetrical two-port network described by z-parameters, which relation must hold?

Az11=z22
Bz12=0
Cz21=0
Dz11=-z22

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Correct Answer: A. z11=z22

Explanation: For a symmetrical two-port, interchanging input and output ports does not change its behavior, giving z11=z22.

Reference: Standard network theory: two-port networks

Question 3

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

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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 4

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

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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 5

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

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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

Question 6

Network TheoryTwo-Port Networks

A reciprocal two-port network described by ABCD parameters satisfies which condition?

AA+D=0
BAD-BC=1
CAB-CD=0
DA=B=C=D

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Correct Answer: B. AD-BC=1

Explanation: With the standard transmission-parameter convention, reciprocity requires the determinant AD-BC to equal 1.

Reference: Standard network theory: two-port networks

Question 7

Network TheoryTwo-Port Networks

For a reciprocal two-port network represented by ABCD parameters, the determinant condition is?

AAD+BC=1
BAD-BC=1
CA+D=1
DB=C=0

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Correct Answer: B. AD-BC=1

Explanation: Using the standard transmission-parameter convention, reciprocity requires AD-BC=1.

Reference: Standard network theory: two-port networks

Question 8

Network TheoryTwo-Port Networks

For a symmetrical two-port network represented by ABCD parameters, which relation holds?

AA=D
BB=C always
CA=0
DD=0

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Correct Answer: A. A=D

Explanation: For a symmetrical two-port, the transmission parameters satisfy A=D.

Reference: Standard network theory: two-port networks

Question 9

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

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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 10

Network TheoryTwo-Port Networks

For z-parameters of a two-port network, the defining equations use port voltages as linear combinations of?

APort currents
BPort powers
COnly source voltages
DOnly load resistances

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Correct Answer: A. Port currents

Explanation: The z-parameter representation is V1=z11 I1+z12 I2 and V2=z21 I1+z22 I2.

Reference: Standard network theory: z-parameters

Question 11

Network TheoryTwo-Port Networks

For a reciprocal two-port represented by z-parameters, which relation must hold?

Az11=z22
Bz12=z21
Cz11=z12
Dz21=0

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Correct Answer: B. z12=z21

Explanation: Reciprocity in the impedance-parameter representation requires the transfer impedances to be equal: z12=z21.

Reference: Standard network theory: reciprocal z-parameters

Question 12

Network TheoryTwo-Port Networks

For a symmetrical two-port represented by z-parameters, which relation holds?

Az11=z22
Bz12=0
Cz21=0
Dz11=z12 always

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Correct Answer: A. z11=z22

Explanation: Symmetry means interchanging the two ports leaves the network behavior unchanged, which requires z11=z22.

Reference: Standard network theory: symmetrical z-parameters

Question 13

Network TheoryTwo-Port Networks

For y-parameters of a two-port network, the port currents are expressed as linear combinations of?

APort voltages
BPort powers
COnly port impedances
DOnly source currents

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Correct Answer: A. Port voltages

Explanation: The admittance representation is I1=y11 V1+y12 V2 and I2=y21 V1+y22 V2.

Reference: Standard network theory: y-parameters

Question 14

Network TheoryTwo-Port Networks

For a reciprocal two-port represented by y-parameters, reciprocity requires?

Ay11=y22
By12=y21
Cy11=0
Dy22=0

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Correct Answer: B. y12=y21

Explanation: For the standard y-parameter sign convention, a reciprocal network satisfies y12=y21.

Reference: Standard network theory: reciprocal y-parameters

Question 15

Network TheoryTwo-Port Networks

The h-parameter h11 of a two-port is an input impedance measured with?

AOutput port short-circuited
BOutput port open-circuited
CInput port open-circuited
DBoth ports disconnected

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Correct Answer: A. Output port short-circuited

Explanation: From V1=h11 I1+h12 V2, setting V2=0 corresponds to an output short circuit, so h11=V1/I1 under that condition.

Reference: Standard network theory: h-parameters

Question 16

Network TheoryTwo-Port Networks

The h-parameter h22 is an output admittance measured with?

AInput port open-circuited
BInput port short-circuited
COutput port open-circuited
DBoth port currents zero

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Correct Answer: A. Input port open-circuited

Explanation: From I2=h21 I1+h22 V2, setting I1=0 means the input port is open, so h22=I2/V2 under that condition.

Reference: Standard network theory: h-parameters

Question 17

Network TheoryTwo-Port Networks

In a two-port network described by inverse-hybrid or g-parameters, the independent variables are?

AV1 and I2
BI1 and V2
CV1 and V2
DI1 and I2

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Correct Answer: A. V1 and I2

Explanation: The g-parameter form uses I1=g11V1+g12I2 and V2=g21V1+g22I2, so V1 and I2 are the independent variables.

Reference: Standard network theory: inverse-hybrid parameters

Question 18

Network TheoryTwo-Port Networks

For a reciprocal two-port represented by h-parameters, the reciprocity condition is?

Ah12=h21
Bh12=-h21
Ch11=h22
Dh11h22=1

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Correct Answer: B. h12=-h21

Explanation: With the standard hybrid-parameter convention, reciprocity requires h12=-h21.

Reference: Standard network theory: reciprocal h-parameters

Question 19

Network TheoryTwo-Port Networks

For a symmetrical two-port represented by ABCD parameters, which condition is required?

AA=D
BB=C
CA=B
DC=D

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Correct Answer: A. A=D

Explanation: Symmetry of a two-port in transmission parameters requires A=D.

Reference: Standard network theory: symmetrical ABCD parameters

Question 20

Network TheoryTwo-Port Networks

A transmission line section represented by ABCD parameters has A=2, B=3 ohm, C=1 siemens and D=2. Is it reciprocal?

AYes, because AD-BC=1
BNo, because AD-BC=7
CYes, because A=D
DNo, because B is not equal to C

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Correct Answer: A. Yes, because AD-BC=1

Explanation: For reciprocity, AD-BC must equal 1. Here 2×2-3×1=1, so the network satisfies the reciprocity condition.

Reference: Standard network theory: ABCD reciprocity numerical

Question 21

Network TheoryTwo-Port Networks

When two two-port networks are connected in parallel at both ports, which parameter matrices are especially convenient to add directly?

Az-parameters
By-parameters
CABCD parameters
Dh-parameters only

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Correct Answer: B. y-parameters

Explanation: For parallel-connected two-ports, corresponding port voltages are common and currents add, making admittance or y-parameters convenient.

Reference: Standard network theory: parallel two-port connection

Question 22

Network TheoryTwo-Port Networks

When two two-port networks are connected in series at both ports, which parameter matrices are especially convenient to add directly?

Az-parameters
By-parameters
CABCD parameters
DS-parameters only

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Correct Answer: A. z-parameters

Explanation: In a series-series interconnection, port currents are common and voltages add, so impedance or z-parameter matrices add directly.

Reference: Standard network theory: series two-port connection

Question 23

Network TheoryTwo-Port Networks

For two cascaded two-port networks, which representation is normally the most convenient because the overall matrix is obtained by ordered multiplication?

Az-parameters
By-parameters
CABCD parameters
Dg-parameters

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Correct Answer: C. ABCD parameters

Explanation: Transmission or ABCD matrices multiply directly in cascade order, which makes them convenient for cascaded networks.

Reference: Standard network theory: cascaded two-port representation

Question 24

Network TheoryTwo-Port Networks

For a two-port with z11=6 ohm, z12=z21=2 ohm and z22=5 ohm, the determinant of the z-parameter matrix is?

A14 ohm squared
B26 ohm squared
C30 ohm squared
D34 ohm squared

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Correct Answer: B. 26 ohm squared

Explanation: The determinant is z11z22-z12z21=6×5-2×2=26 ohm squared.

Reference: Standard network theory: z-matrix determinant numerical

Question 25

Network TheoryTwo-Port Networks

If a two-port z-parameter matrix has determinant Delta_z, the y-parameter matrix, when the inverse exists, is obtained by?

AMultiplying every z-entry by Delta_z
BMatrix inversion of Z
CAdding the four z-parameters
DTransposing Z only

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Correct Answer: B. Matrix inversion of Z

Explanation: The admittance matrix is Y=Z^{-1}, provided det(Z) is nonzero.

Reference: Standard network theory: z-to-y conversion

Question 26

Network TheoryTwo-Port Networks

For Z=[[4,2],[2,3]] ohm, the element y11 of Y=Z^{-1} is?

A0.125 S
B0.25 S
C0.375 S
D0.50 S

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Correct Answer: C. 0.375 S

Explanation: det(Z)=4×3-2×2=8. Z^{-1}=(1/8)[[3,-2],[-2,4]], so y11=3/8=0.375 S.

Reference: Standard network theory: z-to-y conversion numerical

Question 27

Network TheoryTwo-Port Networks

For the same Z=[[4,2],[2,3]] ohm, the transfer admittance y12 is?

A-0.25 S
B+0.25 S
C-0.50 S
D+0.50 S

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Correct Answer: A. -0.25 S

Explanation: From Z^{-1}=(1/8)[[3,-2],[-2,4]], y12=-2/8=-0.25 S.

Reference: Standard network theory: transfer admittance numerical

Question 28

Network TheoryTwo-Port Networks

A reciprocal two-port has z12=3 ohm. What must z21 be?

A-3 ohm
B0 ohm
C3 ohm
D1/3 siemens

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Correct Answer: C. 3 ohm

Explanation: Reciprocity in z-parameters requires z12=z21, hence z21=3 ohm.

Reference: Standard network theory: z-parameter reciprocity numerical

Question 29

Network TheoryTwo-Port Networks

A symmetrical two-port has z11=8 ohm. What must z22 be?

A0 ohm
B4 ohm
C8 ohm
D16 ohm

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Correct Answer: C. 8 ohm

Explanation: For a symmetrical two-port represented by z-parameters, z11=z22.

Reference: Standard network theory: z-parameter symmetry numerical