78.  An effect of phase-lag compensation on servo system performanceis that
A. for a given relative stability, the velocity constant is increased
B. for a given relative stability, the velocity constant is decreased
C. the bandwidth of the system increased
D. the time response is made faster.

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79.  Consider the system x(t) [1 1= 0 1 X(t) + b2 u(t)bi]c(t) = d1d2 X (t)The conditions for complete state controllability and complete observability is2u (s)C(s)e2t0
A. di> 0, b2 >0, bi and d2 can be anything
B. di> 0, d2 > 0, bi and b2 can be anything
C. b1 >0, b2 > 0, di and d2 can be anything
D. bi> 0, b2 >0, bi and d can be anything

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80.  Canonical decomposition of a linear time invariant system is given by
A. completely controllable and observable
B. completely controllable and unobservable
C. uncontrollable but observable
D. neither completely controllable not observable

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81.  Which of the following motors would be suitable for use as servomotors? 1. Two-phase induction motor2.DC separately excited motor3.Single-phase induction motor.4.Universal motor5.Single-phase synchronous motor Select the correct answer using the codes given below :
A. 1, 2, 3, 4 and 5
B. 2, 3 and 4
C. 1, 2 and 5
D. 1 and 5

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82.  In an open loop control system
A. control action is independent of the output
B. control action depends on human judgement automatically taken care of
C. Viscous friction coefficient is analogous to conductance
D. both A and B above

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83.  In a closed loop control system
A. control action depends on the output and also on the input command
B. output signal is feedback to be compared with the reference signal
C. the accuracy is better than in open loop system
D. all of these

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84.  A servomechanism is a feedback control system required to control
A. position
B. a derivative of position
C. either A or B above
D. none of the above

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