Network Theory Questions and Answers Part-6

1. Mesh analysis is applicable for non planar networks also.
a) true
b) false

Answer: b
Explanation: Mesh analysis is applicable only for planar networks. A circuit is said to be planar if it can be drawn on a plane surface without crossovers.

2. A mesh is a loop which contains ____ number of loops within it.
a) 1
b) 2
c) 3
d) no loop

Answer: d
Explanation: A loop is a closed path. A mesh is defined as a loop which does not contain any other loops within it.

3. Consider the circuit shown below. The number mesh equations that can be formed are?
53
a) 1
b) 2
c) 3
d) 4

Answer: b
Explanation: We know if there are n loops in the circuit, n mesh equations can be formed. So as there are 2 loops in the circuit. So 2 mesh equations can be formed.

4. In the figure shown below, the current through loop 1 be I1 and through the loop 2 be I2, then the current flowing through the resistor R2 will be?
4
a) I1
b) I2
c) I1-I2
d) I1+I2

Answer: c
Explanation: Through the resistor R2 both the currents I1, I2 are flowing. So the current through R2 will be I1-I2.

5. If there are 5 branches and 4 nodes in graph, then the number of mesh equations that can be formed are?
a) 2
b) 4
c) 6
d) 8

Answer: a
Explanation: Number of mesh equations = B-(N-1). Given number of branches = 5 and number of nodes = 4. So Number of mesh equations = 5-(4-1) = 2.

6. Consider the circuit shown in the figure. Find voltage Vx.
56
a) 1
b) 1.25
c) 1.5
d) 1.75

Answer: b
Explanation: Consider current I1 (CW) in the loop 1 and I2 (ACW) in the loop 2. So, the equations will be Vx+I2-I1=0. I1=5/2=2.5A. I2=4Vx/4= Vx. Vx+Vx-2.5=0. Vx = 1.25V.

7. Consider the circuit shown below. Find the current I1 (A).
57
a) 3.32
b) 3.78
c) 5.33
d) 6.38

Answer: b
Explanation: According to mesh analysis,
(1+3+6)I1 – 3(I2) – 6(I3) = 10
-3(I1) + (2+5+3)I2 = 4
-6(I1) + 10(I3) = – 4 + 20
On solving the above equations, we get I1 = 3.78A.

8. Consider the following figure. Find the current I3 (A).
58
a) 4.34
b) 3.86
c) 5.45
d) 5.72

Answer: b
Explanation: According to mesh analysis,
(1+3+6)I1 – 3(I2) – 6(I3) = 10
-3(I1) + (2+5+3)I2 = 4
-6(I1) + 10(I3) = – 4 + 20
On solving the above equations, we get I3 = 3.86A.

9. Consider the circuit shown below. Find the current I1 (A).
59
a) 1
b) 1.33
c) 1.66
d) 2

Answer: b
Explanation: Applying Super mesh analysis, the equations will be I2-I1=2 -10+2I1+I2+4=0. On solving the above equations, I1=1.33A.

10. Consider the circuit shown below. Find the current I2 (A).
60
a) 1.33
b) 2.33
c) 3.33
d) 4.33

Answer: c
Explanation: Applying Super mesh analysis, the equations will be I2-I1=2
-10+2I1+I2+4=0. On solving the above equations, I2=3.33A.