Control Systems – Multiple Choice Questions (MCQs)

1. 73. The final value theorem is valid only if the poles of sF(s) are in the:

   • A. Right half of s-plane
   • B. Left half of s-plane
   • C. Imaginary axis
   • D. Origin

2. 74. A system with poles on the imaginary axis (excluding the origin) is considered:

   • A. Stable
   • B. Unstable
   • C. Marginally stable
   • D. Conditionally stable

3. 75. The term "loop gain" in a feedback control system refers to the product of the gains of:

   • A. Forward path and feedback path
   • B. Forward path only
   • C. Feedback path only
   • D. Input and output

4. 76. Which of the following is a common method for stability analysis in the frequency domain?

   • A. Routh-Hurwitz
   • B. Root Locus
   • C. Nyquist Plot
   • D. Mason's gain formula

5. 77. A lag compensator primarily affects the system's performance at:

   • A. High frequencies
   • B. Low frequencies
   • C. Mid frequencies
   • D. All frequencies

6. 78. A lead compensator primarily affects the system's performance at:

   • A. High frequencies
   • B. Low frequencies
   • C. Mid frequencies
   • D. All frequencies

7. 79. The state variables of a system are variables that describe the system's:

   • A. Input
   • B. Output
   • C. Internal state
   • D. Disturbances

8. 80. For a stable system

   • A. the number of encirclements of the -1 point in the Nyquist plot is equal to the number of:
   • B. Poles of open-loop transfer function
   • C. Zeros of open-loop transfer function
   • D. Poles of closed-loop transfer function in RHP

9. 81. The "rise time" in a step response is the time taken for the output to rise from:

   • A. 0% to 100% of final value
   • B. 10% to 90% of final value
   • C. 50% to 90% of final value
   • D. 0% to 50% of final value

10. 82. The "peak time" in a step response is the time taken to reach the:

    • A. First peak overshoot
    • B. Final value
    • C. Steady-state
    • D. Settling time

11. 83. The "delay time" in a step response is the time taken for the output to reach:

    • A. 50% of final value
    • B. 10% of final value
    • C. 90% of final value
    • D. 100% of final value

12. 84. What is the main advantage of using a PID controller?

    • A. Simplicity
    • B. Robustness
    • C. Versatility in controlling various systems
    • D. Low cost