Circuit Theory – Multiple Choice Questions (MCQs)

1. 121. What is "impedance" in an AC circuit?

   • A. The total opposition to current flow
   • B. The resistance only
   • C. The reactance only
   • D. The conductance

2. 122. The unit of impedance is:

   • A. Farad
   • B. Henry
   • C. Ohm
   • D. Siemens

3. 123. What is "reactance"?

   • A. The opposition to current flow offered by resistors
   • B. The opposition to current flow offered by capacitors and inductors
   • C. The total opposition to current flow
   • D. The flow of current

4. 124. What is "admittance"?

   • A. The reciprocal of resistance
   • B. The reciprocal of impedance
   • C. The reciprocal of reactance
   • D. The reciprocal of conductance

5. 125. The unit of admittance is:

   • A. Ohm
   • B. Siemens
   • C. Farad
   • D. Henry

6. 126. What is the power factor in a purely resistive AC circuit?

   • A. 0
   • B. 0.5
   • C. 1
   • D. 0.707

7. 127. What is the power factor in a purely inductive AC circuit?

   • A. 0
   • B. 0.5
   • C. 1
   • D. 0.707

8. 128. What is the power factor in a purely capacitive AC circuit?

   • A. 0
   • B. 0.5
   • C. 1
   • D. 0.707

9. 129. The quality factor (Q-factor) of a series RLC circuit is a measure of its:

   • A. Resistance
   • B. Selectivity
   • C. Inductance
   • D. Capacitance

10. 130. What is "superposition theorem" used for?

    • A. To find power in linear circuits
    • B. To find current and voltage in linear circuits with multiple sources
    • C. To find resistance
    • D. To find capacitance

11. 131. Superposition theorem cannot be used for calculating:

    • A. Current
    • B. Voltage
    • C. Power
    • D. Resistance

12. 132. Norton's theorem states that any linear circuit can be replaced by an equivalent circuit containing:

    • A. A voltage source and a series resistor
    • B. A current source and a parallel resistor
    • C. A capacitor and an inductor
    • D. Two voltage sources