Circuit Theory – Multiple Choice Questions (MCQs)

1. 85. The total instantaneous power in an AC circuit is given by:

   • A. V_rms * I_rms
   • B. V_peak * I_peak
   • C. P + Q
   • D. v(t) * i(t)

2. 86. The concept of "phasors" is applicable only to:

   • A. DC circuits
   • B. Sinusoidal AC circuits
   • C. Non-linear circuits
   • D. Transient circuits

3. 87. What is a "balanced three-phase system"?

   • A. A system where phase voltages and currents are unequal
   • B. A system where the phase voltages and currents are equal in magnitude and displaced by 120 degrees electrically
   • C. A system with only two phases
   • D. A system with a single phase

4. 88. What is "symmetrical components" method used for?

   • A. Analyzing balanced three-phase systems
   • B. Analyzing unbalanced three-phase systems
   • C. Analyzing single-phase systems
   • D. Analyzing DC systems

5. 89. The "delta-wye transformation" is used to:

   • A. Convert a star connection to a delta connection
   • B. Simplify complex circuits
   • C. Analyze three-phase systems
   • D. All of the above

6. 90. What is a "coupled circuit"?

   • A. A circuit with only one inductor
   • B. A circuit containing mutually inductive elements
   • C. A circuit with no resistors
   • D. A circuit with only capacitors

7. 91. The "dot convention" for mutually coupled coils is used to indicate:

   • A. The number of turns
   • B. The polarity of mutually induced voltage
   • C. The resistance of the coils
   • D. The capacitance of the coils

8. 92. What is "network graph" in circuit theory?

   • A. A diagram showing only resistors
   • B. A topological representation of a circuit showing nodes and branches
   • C. A graph plotting voltage vs current
   • D. A graph showing power consumption

9. 93. What is a "tree" in a network graph?

   • A. A closed path
   • B. A subgraph that connects all nodes without forming any closed loops
   • C. A single branch
   • D. A node

10. 94. What is a "cotree" in a network graph?

    • A. The set of branches not included in the tree
    • B. The set of branches forming a closed loop
    • C. The set of nodes
    • D. The set of all branches

11. 95. The number of independent KCL equations for a circuit with N nodes is:

    • A. N
    • B. N-1
    • C. N+1
    • D. 2N

12. 96. The number of independent KVL equations for a planar circuit with B branches and N nodes is:

    • A. B-N+1
    • B. N-1
    • C. B+N-1
    • D. N