Control Systems – Multiple Choice Questions (MCQs)

1. 49. The type of a system is determined by the number of poles at the origin of the ________ function.

   • A. Open-loop transfer
   • B. Closed-loop transfer
   • C. Feedback
   • D. Forward path

2. 50. A system is critically damped when its damping ratio is:

   • A. 0
   • B. 1
   • C. Less than 1
   • D. Greater than 1

3. 51. The settling time of a second-order system is approximately how many time constants for a 2% criterion?

   • A. 2
   • B. 3
   • C. 4
   • D. 5

4. 52. The corner frequency in a Bode plot corresponds to the break point in the magnitude and phase characteristics of a:

   • A. Pole or zero
   • B. Gain
   • C. Integrator
   • D. Differentiator

5. 53. What is the main characteristic of a feedback control system?

   • A. Accuracy
   • B. Simplicity
   • C. Low cost
   • D. Insensitivity to disturbances

6. 54. The gain crossover frequency is the frequency at which the magnitude of the open-loop transfer function is:

   • A. 0 dB
   • B. 1 dB
   • C. 10 dB
   • D. -10 dB

7. 55. The phase crossover frequency is the frequency at which the phase angle of the open-loop transfer function is:

   • A. 0 degrees
   • B. -90 degrees
   • C. -180 degrees
   • D. -270 degrees

8. 56. Which of the following methods is used to determine the relative stability of a system?

   • A. Routh-Hurwitz
   • B. Root Locus
   • C. Nyquist Plot
   • D. All of the above

9. 57. The term "overshoot" refers to:

   • A. The time taken to reach the final value
   • B. The maximum deviation of the output from its final value
   • C. The steady-state error
   • D. The oscillations in the response

10. 58. A system with a transfer function 1/s is a:

    • A. Integrator
    • B. Differentiator
    • C. Proportional controller
    • D. Lead compensator

11. 59. The block diagram reduction technique relies on algebraic manipulation of:

    • A. Transfer functions
    • B. Time domain equations
    • C. Frequency domain equations
    • D. State-space equations

12. 60. What is the effect of negative feedback on system gain?

    • A. Increases gain
    • B. Decreases gain
    • C. No effect on gain
    • D. Makes gain infinite