Automatic Control System MCQ-4

1. Traffic light system is the example of :

(A) Open loop system
(B) Closed loop system
(C) Both (a) and (b)
(D) None of these

2. The gain margin of a second order system is

(A) Zero
(B) Infinite
(C) One
(D) Two

3. The most powerful controller is :

(A) PD controller
(B) PI PI contoller
(C) PID controller
(D) None of these

4. A control system with excessive noise, is likely to suffer from

(A) Saturation in amplifying stages.
(B) Loss of gain
(C) Vibrations
(D) Oscillations

5. The most commonly used input signal(s) in control system is/are

(A) Step function
(B) Ramp or velocity function
(C) Accelerating function
(D) All of the above

6. When the gain K is increased the system become :

(A) More stable
(B) Less stabe
(C) Unstable
(D) None of these

7. An ideal potentiometer should have :

(A) Zero resolution
(B) Infinite resolution
(C) A fime wire
(D) A thick wire

8. A static variable approach can be applied to _____ system

(A) Time variant
(B) Non linear
(C) Linear and time invariant
(D) All of the above

9. The transfer function of a system is given as 100/(S²+20S+100), The system is

(A) An over damped system
(B) A critically damped system
(C) An under damped system
(D) An unstable system

10. For handling multiple input multiple output system which one of the following is used :

(A) State variable approach
(B) Bode plot
(C) Nyquist plot
(D) Rootlocus technique

11. Phase margin of a system is used to specify :

(A) Relative stability
(B) Absolute stability
(C) Time response
(D) Steady state error

12. When the input frequency is varied from zero to infinity causing variations in magnitude and phase angle, the traced locus by phaser is called :

(A) Bode plot
(B) Polar plot
(C) Root locus
(D) Nyquist plot

13. A system with gain margin close to unity or a phase marigin close to zero is :

(A) Highly stable
(B) Oscillatory
(C) Highly unstable
(D) None of these

14. If the bandwidth of a system is increased the system response will

(A) Remain unaffected
(B) Become faster
(C) Become slower
(D) None of these

15. The characteristic equation of a feedback control system is 2S^4+S³+3S²+5S+10=0. The number of roots in the right-half S plane is :

(A) Zero
(B) 1
(C) 2
(D) 3

16. For a stable system, the phase margin :

(A) Is always positive
(B) Is always negative
(C) May be positive and negative
(D) None of these

17. A system has a single pole at the origin, its impulse response is :

(A) Constant
(B) Ramp
(C) Decaying exponential
(D) Oscillatory

18. Gain margin in the factor by which the system gain can be increased to drive it to the verge of :

(A) Stability
(B) Instability
(C) Oscillation
(D) Critical damping

19. Which one of the following element is not required in an automatic control system.

(A) Error detector
(B) Sensor
(C) Oscillator
(D) All of the above

20. The largest error between reference input and output during the transient period is called

(A) Peak error
(B) Transient overshoot
(C) Peak overshoot
(D) Transient deviation