Network Theory Multiple Choice Questions on “Superposition Theorem”.
1. In Superposition theorem, while considering a source, all other voltage sources are?
A. open circuited
B. short circuited
C. change its position
D. removed from the circuit
Answer: B
Clarification: In Superposition theorem, while considering a source, all other voltage sources are short circuited. This theorem is valid for linear systems.
2. In Superposition theorem, while considering a source, all other current sources are?
A. short circuited
B. change its position
C. open circuited
D. removed from the circuit
Answer: C
Clarification: In Superposition theorem, while considering a source, all other current sources are open circuited. Superposition theorem is not valid for power responses. It is applicable only for computing voltage and current responses.
3. In the circuit shown, find the current through 4Ω resistor using Superposition theorem.
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A. 4
B. 5
C. 6
D. 7
Clarification: Considering the voltage source 20V, 5A current source is open circuited.
Now current through 3Ω resistor is 20/(5+4)=2.22A.
Now considering the current source 5A, 20V voltage source is short circuited.
No current through 3Ω resistor is 5 × 5/(4+5)=2.78A. Now finally the current through 3Ω resistor is 2.22 + 2.78 = 5A.
4. Consider the circuit shown below. Find the voltage across 2Ω resistor due to the 10V voltage source using Superposition theorem.
A. 0
B. 1
C. 2
D. 3
Clarification: Short circuiting 20V source, open circuiting 2A source,
5. Find the voltage across 2Ω resistor due to 20V source in the following figure.
A. -2.92
B. 2.92
C. 1.92
D. -1.92
Clarification: Short circuiting 10V source, open circuiting 2A source,
The voltage at node A is (V-20)/7+V/20+V/10=0 => V = 9.76V. Now the voltage across 2Ω resistor is (V-20)/7×2=-2.92V.
6. Find the voltage across 2Ω resistor due to 2A source in the following figure.
A. -1
B. 1
C. 1.46
D. -1.46
Clarification: Short circuiting both 10V, 20V sources,
The current through 2Ω resistor is 2× 5/(5+8.67)=0.73A. The voltage across 2Ω resistor is -0.73×2 = -1.46V.
7. In the figure shown below. Find the voltage across 2Ω resistor due to all source using Superposition theorem.
A. 3.41
B. -3.41
C. 3.14
D. -3.14
Answer: B
Clarification: The algebraic sum of all the voltages obtained by considering individual sources is the voltage across 2Ω resistor. V = 0.97-2.92-1.46 = -3.41V.
8. Find the voltage across 2Ω resistor due to 20V source in the circuit shown below.
A. 1
B. 1.5
C. 2
D. 2.5
Clarification: The voltage at node A in the figure is (V-20)/20+(V-10)/10+V/2=0 => V=3.07V. Now short circuiting 10V source,
(V-20)/20+V/2+V/10=0 => V=1.5V.
9. Find the voltage across 2Ω resistor due to 20V source in the following circuit.
A. 0.5
B. 0
C. 1
D. 1.5
Clarification: The voltage at node A is (V-20)/20+(V-10)/10+V/2=0 => V=3.07V. Now short circuiting 20V source,
(V-10)/10+V/20+V/2=0 => V=1.5V.
10. Find the voltage across 2Ω resistor in the circuit shown below using Superposition theorem.
A. 1
B. 2
C. 3
D. 4
Answer: C
Clarification: The voltage across 2Ω resistor is the algebraic sum of the voltages obtained by considering individual sources. V = 1.5+1.5 = 3V.