250+ TOP MCQs on Thevenin’s Theorem and Answers

Network Theory Multiple Choice Questions on “Thevenin’s Theorem”.

1. Consider the circuit shown below. Find the equivalent Thevenin’s voltage between nodes A and B.

A. 8
B. 8.5
C. 9
D. 9.5

Answer: B
Clarification: The thevenin’s voltage is equal to the open circuit voltage across the terminals AB that is across 12Ω resistor. V_th = 10×12/14 = 8.57V.

2. Consider the circuit shown below. Find the thevenin’s resistance between terminals A and B.

A. 1
B. 2
C. 1.7
D. 2.7

Answer: C
Clarification: The resistance into the open circuit terminals is equal to the thevenin’s resistance => R_th = (12×2)/14 = 1.71Ω.

3. Consider the circuit shown below. Find the current flowing through 24Ω resistor.

A. 0.33
B. 0.66
C. 0
D. 0.99

4. Determine the equivalent thevenin’s voltage between terminals A and B in the circuit shown below.

A. 0.333
B. 3.33
C. 33.3
D. 333

Answer: C
Clarification: Let us find the voltage drop across terminals A and B. 50-25=10I+5I => I=1.67A. Voltage drop across 10Ω resistor = 10×1.67=16.7V. So, V_th=V_AB=50-V=50-16.7=33.3V.

5. Find the equivalent thevenin’s resistance between terminals A and B in the circuit shown below.

A. 333
B. 33.3
C. 3.33
D. 0.333

Answer: C
Clarification: To find R_th, two voltage sources are removed and replaced with short circuit. The resistance at terminals AB then is the parallel combination of the 10Ω resistor and 5Ω resistor => R_th=(10×5)/15=3.33Ω.

6. Determine the equivalent thevenin’s voltage between terminals A and B in the circuit shown below.

A. 5
B. 15
C. 25
D. 35

Answer: C
Clarification: Current through 3Ω resistor is 0A. The current through 6Ω resistor = (50-10)/(10+6)=2.5A. The voltage drop across 6Ω resistor = 25×6=15V. So the voltage across terminals A and B = 0+15+10 = 25V.

7. Find the equivalent thevenin’s resistance between terminals A and B in the following circuit.

A. 6
B. 6.25
C. 6.5
D. 6.75

Answer: D
Clarification: To find R_th, two voltage sources are removed and replaced with short circuit => R_th=(10×6)/(10+6)+3=6.75Ω.

8. Determine the equivalent thevenin’s voltage between terminals ‘a’ and ‘b’ in the circuit shown below.

A. 0.7
B. 1.7
C. 2.7
D. 3.7

Answer: C
Clarification: The voltage at terminal a is V_a=(100×6)/16=37.5V, The voltage at terminal b is V_b=(100×8)/23=34.7V. So the voltage across the terminals ab is V_ab=V_a-V_b=37.5-34.7=2.7V.

9. Find the equivalent thevenin’s resistance between terminals A and B in the circuit shown below.

A. 6
B. 7
C. 8
D. 9

Answer: D
Clarification: To find R_th, two voltage sources are removed and replaced with short circuit => R_ab=(6×10)/(6+10)+(8×15)/(8+15)=8.96≅9V.

10. Find the current through 5Ω resistor in the following circuit.

A. 0.1
B. 0.2
C. 0.3
D. 0.4