## Network Theory MCQ Set 1

1.In the circuit shown below, find the transmission parameter A.

a) 6/5

b) 5/6

c) 3/4

d) 4/3

### View Answer

^{‘}, V

_{1}= 6 I

_{1}, V

_{2}= 5I

_{1}. On solving V

_{1}/V

_{2}= 6/5. On substituting we get A = V

_{1}/V

_{2}=6/5.

2. In the circuit shown above, find the transmission parameter C.

a) 4/5

b) 3/5

c) 2/5

d) 1/5

### View Answer

_{1}/V

_{2}|I

_{2}=0. By open circuiting b-b

^{‘}we get V

_{2}= 5 I

_{1}=>I

_{1}/V

_{2}= 1/5. On substituting we get C = I

_{1}/V

_{2}=1/5 Ω.

3. In the circuit shown above, find the transmission parameter B.

a) 15/5

b) 17/5

c) 19/5

d) 21/5

### View Answer

_{1}/I

_{2}|V

_{2}=0. Short circuiting b-b

^{‘}, -I

_{2}= 5/17 V

_{1}=> -V

_{1}/I

_{2}= 17/5. On substituting we get B=17/5 Ω.

4. In the circuit shown above, find the transmission parameter D.

a) 1/5

b) 3/5

c) 7/5

d) 9/5

### View Answer

_{1}/I

_{2}|V

_{2}=0. Short circuiting b-b

^{‘}, I

_{1}= 7/17 V

_{1}and-I

_{2}= 5/17 V

_{1}. So we get I

_{1}/I

_{2}= 7/5. So D=7/5.

5. The hybrid parameter h_{11} is called?

a) short circuit input impedance

b) short circuit forward current gain

c) open circuit reverse voltage gain

d) open circuit output admittance

### View Answer

_{11}=V

_{1}/I

_{1}|V

_{2}=0. So the hybrid parameter h

_{11}is called short circuit input impedance.

6. The hybrid parameter h_{21} is called?

a) open circuit output admittance

b) open circuit reverse voltage gain

c) short circuit forward current gain

d) short circuit input impedance

### View Answer

_{21}=I

_{2}/I

_{1}|V

_{2}=0. So the hybrid parameter h

_{21}is called short circuit forward current gain.

7. In the circuit shown below, find the h-parameter h_{11}.

a) 1

b) 2

c) 3

d) 4

### View Answer

_{11}=V

_{1}/I

_{1}|V

_{2}=0. So short circuiting b-b

^{‘}, V

_{1}= I

_{1}((2||2)+1) = 2I

_{1}=> V

_{1}/I

_{1}= 2. On substituting we get h

_{11}= V

_{1}/I

_{1}= 2Ω.

8. In the circuit shown in question 7, find the h-parameter h_{21}.

a) 1

b) -1

c) 1/2

d) -1/2

### View Answer

^{‘}, h

_{21}= I

_{2}/I

_{1}when V

_{2}=0 and -I

_{2}= I

_{1}/2 => I

_{2}/I

_{1}= -1/2. So h

_{21}= -1/2.

9. In the circuit shown in question 7, find the h-parameter h_{12}.

a) 1/2

b) -1/2

c) 1

d) -1

### View Answer

^{‘}we get V

_{1}=I

_{y}×2 and I

_{y}=I

_{2}/2 and V

_{2}=I

_{x}×4 and I

_{x}=I

_{2}/2. On solving and substituting, we get h

_{12}=V

_{1}/V

_{2}=1/2.

10. In the circuit shown in question 7, find the h-parameter h_{22}.

a) 1

b) 2

c) 1/2

d) 3/2

### View Answer

^{‘}we get V

_{1}=I

_{y}×2 and I

_{y}=I

_{2}/2 and V

_{2}=I

_{x}×4 and I

_{x}=I

_{2}/2. On solving and substituting, we get h

_{22}=I

_{2}/V

_{2}=1/2 Ω.

## Network Theory MCQ Set 2

1. A graph is said to be a directed graph if ________ of the graph has direction.

a) 1 branch

b) 2 branches

c) 3 branches

d) every branch

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2. The number of branches incident at the node of a graph is called?

a) degree of the node

b) order of the node

c) status of the node

d) number of the node

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3. If no two branches of the graph cross each other, then the graph is called?

a) directed graph

b) undirected graph

c) planar graph

d) non-planar graph

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4. Consider the graph given below. Which of the following is a not a tree to the graph?

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5. Number of twigs in a tree are? n- number of nodes

a) n

b) n+1

c) n-1

d) n-2

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6. Loops which contain only one link are independent are called?

a) open loops

b) closed loops

c) basic loops

d) none of the above

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7. If the incident matrix of a graph is given below. The corresponding graph is?

a b c d e f 1 +1 0 +1 0 0 +1 2 -1 -1 0 +1 0 0 3 0 +1 0 0 +1 -1 4 0 0 -1 -1 -1 0

### View Answer

a b c d e f 1 +1 0 +1 0 0 +1 2 -1 -1 0 +1 0 0 3 0 +1 0 0 +1 -1 4 0 0 -1 -1 -1 0

the corresponding graph is ‘b’ considering the directions specified in the graph.

8. If A represents incidence matrix, I represents branch current vectors, then?

a) AI = 1

b) AI = 0

c) AI = 2

d) AI= 3

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9. If a graph consists of 5 nodes, then the number of twigs in the tree are?

a) 1

b) 2

c) 3

d) 4

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10. If there are 4 branches, 3 nodes then number of links in a co-tree are?

a) 2

b) 4

c) 6

d) 8

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## Network Theory MCQ Set 3

1. In star connected system, V_{RY} is equal to?

a) V_{YR}

b) -V_{YR}

c) 2V_{YR}

d) 3V_{YR}

### View Answer

_{RY}= – V

_{YR}.

2. In three phase system, the line voltage V_{RY} is equal to?

a) phasor sum of V_{RN} and V_{NY}

b) phasor difference of V_{RN} and V_{NY}

c) phasor sum of V_{RN} and V_{NY}

d) algebraic sum of V_{RN} and V_{NY}

### View Answer

_{RY}is equal to the phasor sum of V

_{RN}and V

_{NY}which is also equal to the phasor difference of V

_{RN}and V

_{YN}.

3. The relation between the lengths of the phasors V_{RN} and – V_{YN} is?

a) |V_{RN}| > – |V_{YN}|

b) |V_{RN}| < – |V_{YN}|

c) |V_{RN}| = – |V_{YN}|

d) |V_{RN}| >= – |V_{YN}|

### View Answer

_{RY}is found by compounding V

_{RN}and V

_{YN}reversed. The relation between the lengths of the phasors V

_{RN}and – V

_{YN}is |V

_{RN}|= – |V

_{YN}|.

4. In a star connected system, the phasors V_{RN} , V_{YN} are ____ apart.

a) 15⁰

b) 30⁰

c) 45⁰

d) 60⁰

### View Answer

_{RN}, V

_{YN}are separated by θ= 60⁰. To subtract V

_{YN}from V

_{RN}, we reverse the phase V

_{YN}and find its phasor sum with V

_{RN}.

5. The relation between V_{RY} ,Vph in a star connected system is?

a) V_{RY} =V_{ph}

b) V_{RY} =√3V_{ph}

c) V_{RY} =3√3V_{ph}

d) V_{RY} =3V_{ph}

### View Answer

_{YN}and V

_{BN}are equal in length and are 60⁰apart. The relation between V

_{RY},V

_{ph}in a star connected system is V

_{RY}= √3V

_{ph}.

6. In a star connected system, the relation between V_{YB} ,V_{ph} is?

a) V_{YB} =V_{ph}

b) V_{YB} =3√3V_{ph}

c) V_{YB} =3V_{ph}

d) V_{YB} =√3V_{ph}

### View Answer

_{YB},V

_{ph}is V

_{YB}= √3V

_{ph}. The line voltage V

_{YB}is equal to the phasor difference of V

_{YN}and V

_{BN}and is equal to √3V

_{ph}.

7. The voltages, V_{BR} ,V_{ph} are related in star connected system is?

a) V_{BR} =3V_{ph}

b) V_{BR} =3√3V_{ph}

c) V_{BR} =√3V_{ph}

d) V_{BR} =V_{ph}

### View Answer

_{BR},V

_{ph}in star connected system are related as V

_{BR}=√3V

_{ph}. The line voltage V

_{YB}is equal to the phasor difference of V

_{BN}and V

_{RN}and is equal to √3V

_{ph}.

8. A symmetrical star connected system has V_{RN} =230∠0⁰. The phase sequence is RYB. Find V_{RY}.

a) 398.37∠30⁰

b) 398.37∠-30⁰

c) 398.37∠90⁰

d) 398.37∠-90⁰

### View Answer

_{RN}= 230∠0⁰V. V

_{RY}= √3×230∠(0

^{o}+30

^{o})V=398.37∠30

^{o}V.

9. Find V_{YB} in the figure shown in question 8.

a) 398.37∠-30⁰

b) 398.37∠210⁰

c) 398.37∠90⁰

d) 398.37∠-90⁰

### View Answer

_{YN}= 230∠-120⁰V. V

_{YB}= √3×230∠(-120

^{o}+30

^{o})V=398.37∠-90⁰V.

10. Find V_{BR} in the figure shown in question 8.

a) 398.37∠210⁰

b) 398.37∠-210⁰

c) 398.37∠120⁰

d) 398.37∠-120⁰

### View Answer

_{BN}= 230∠-240⁰V. V

_{BR}= √3×230∠(-240

^{o}+30

^{o})V=398.37∠-210

^{o}V.

## Network Theory MCQ Set 4

1. Two ports containing no sources in their branches are called?

a) active ports

b) passive ports

c) one port

d) three port

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2. Two ports containing sources in their branches are called?

a) three port

b) one port

c) passive ports

d) active ports

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3. In determining open circuit impedance parameters, among V_{1}, V_{2}, I_{1}, I_{2}, which of the following are dependent variables?

a) V_{1} and V_{2}

b) I_{1} and I_{2}

c) V_{1} and I_{2}

d) I_{1} and V_{2}

### View Answer

_{1}, V

_{2}, I

_{1}, I

_{2}; V

_{1}and V

_{2}are dependent variables and I

_{1}, I

_{2}are independent variables i.e., dependent variables depend on independent variables.

4. In determining open circuit impedance parameters, among V_{1}, V2, I_{1}, I2, which of the following are independent variables?

a) I_{1} and V_{2}

b) V_{1} and I_{2}

c) I_{1} and I_{2}

d) V_{1} and V_{2}

### View Answer

_{1}, V

_{2}, I

_{1}, I

_{2}; I

_{1}and I

_{2}are independent variables and V

_{1}, V

_{2}are dependent variables. Independent variables are the variables that do not depend on any other variable.

5. Which of the following expression is true in case of open circuit parameters?

a) V_{1} = Z_{11} V_{1} + Z_{12} I_{2}

b) V_{1} = Z_{11}I_{1} + Z_{12} V_{2}

c) V_{1} = Z_{11}I_{1} + Z_{12} I_{2}

d) V_{2} = Z_{11}I_{1} + Z_{12} I_{2}

### View Answer

_{11}, Z

_{12}and currents I

_{1}, I

_{2}and voltage V

_{1}is V

_{1}= Z

_{11}I

_{1}+ Z

_{12}I

_{2}.

6. Which of the following expression is true in case of open circuit parameters?

a) V_{2} = Z_{21}I_{2} + Z_{22} I_{2}

b) V_{2} = Z_{21}I_{1} + Z_{22} I_{2}

c) V_{1} = Z_{21}I_{2} + Z_{22} I_{2}

d) V_{1} = Z_{21}I_{1} + Z_{22} I_{2}

### View Answer

_{1}, I

_{2}and voltage V

_{1}and open circuit parameters Z

_{21}, Z

_{22}is V

_{2}= Z

_{21}I

_{1}+ Z

_{22}I

_{2}.

7. Find the Z – parameter Z_{11} in the circuit shown below.

a) 1

b) 1.5

c) 2

d) 2.5

### View Answer

_{11}, the current I

_{2}is equal to zero. Now we obtain Z

_{eq}as 1+ (6×2)/(6+2)=2.5Ω. So, Z

_{11}= 2.5Ω.

8. The value of Z_{21} in the circuit shown in the question 7 is?

a) 0

b) 1

c) 2

d) 3

### View Answer

_{2}is the voltage across the 4Ω impedance. The current through 4Ω impedance is I

_{1}/4. And V

_{2}= (I

_{1}/4) x 4 = I

_{1}. So, Z

_{21}= 1Ω.

9. Find the value of Z_{12} in the circuit shown in the question 7.

a) 3

b) 2

c) 1

d) 0

### View Answer

_{2}/2. So, V

_{1}= 2 x (I

_{2}/2). On solving and substituting we get Z

_{12}= 1Ω.

10. Determine the value of Z_{22} in the circuit shown in the question 7.

a) 0

b) 1

c) 2

d) 3

### View Answer

_{2}= I

_{2}((2+2)||4) => V

_{2}= I

_{2}x 2 =>V

_{2}/I

_{2}= 2. Therefore the value of Z

_{22}is 2Ω.

## Network Theory MCQ Set 5

1. Consider the impedance function Z(s)=3(s+2)(s+4)/(s+1)(s+3) . Find the value of R_{1} after realizing by first Foster method.

a) 9/2

b) 2/9

c) 9

d) 1/9

### View Answer

_{1}is 9/2Ω.

2. Find the value of C_{1} in question 1.

a) 1/9

b) 9

c) 2/9

d) 9/2

### View Answer

_{1}= 1/C

_{1}, we get the 1/C

_{1}value as 9/2. So the value of C

_{1}is 2/9 F. C

_{1}= 2/9 F.

3. Find the value of C_{2} in question 1.

a) 1/3

b) 3

c) 3/2

d) 2/3

### View Answer

_{2}= 1/C

_{2}. The value of P

_{2}is 3/2. So the value of C

_{2}is 2/3 F. C

_{2}= 2/3 F.

4. Find the value of R_{2} in question 1.

a) 1

b) 1/2

c) 1/4

d) 1/8

### View Answer

_{2}C

_{2}= 3. And the value of C

_{2}is 2/3 F. So the value of R

_{2}is ½Ω. R

_{2}= ½Ω.

5. Find the value of R_{∞} in question 1.

a) 1

b) 2

c) 3

d) 4

### View Answer

_{∞}is 3Ω. R

_{∞}= 3Ω.

6. Consider the impedance function Y(s)=(s^{2}+4s+3)/(3s^{2}+18s+24). Find the value of R_{0} after realizing by second Foster method.

a) 4

b) 8

c) 12

d) 16

### View Answer

_{0}as 1/8. So the value of R

_{0}is 8Ω. R

_{0}= 8Ω.

7. Find the value of R_{1} in question 6.

a) 16

b) 12

c) 8

d) 4

### View Answer

_{1}as 1/12. And we know that R

_{1}=1/P

_{1}. So the value of R

_{1}is 12Ω. R

_{1}= 12Ω.

8. Find the value of C_{1} in question 6.

a) 1/24

b) 1/12

c) 1/6

d) 1/3

### View Answer

_{1}is 1/((2)(R

_{1})). As R

_{1}is 12Ω, the value of C

_{1}is 1/24 F. C

_{1}= 1/24 F.

9. Find the value of R_{2} in question 6.

a) 5

b) 6

c) 7

d) 8

### View Answer

_{2}on taking the partial fractions as 1/8. And we know R

_{2}= 1/P

_{2}So the value of R

_{2}is 8Ω. So, R

_{2}= 8Ω.

10. Determine the value of C_{2} in question 6.

a) 1/16

b) 1/8

c) 1/32

d) 1/64

### View Answer

_{2}as 8Ω and we know C

_{2}= 1/((4)(R

_{2})). So the value of C

_{2}is 1/32 F. C

_{2}= 1/32 F.