Control System Competitive Questions with Answers: Part-4

Control System Competitive Questions with Answers: Part-4

CONTROL SYSTEM SOLVED COMPETITIVE QUESTIONS:

[1] An open loop system represented by the transfer function G(s) = (s-1) / (s+2)(s+3) is
A. stable and of the minimum phase type
B. stable and of the non-minimum phase type
C. unstable and of the minimum phase type
D. unstable and of the non-minimum phase type

Ans:B

[2] The open loop transfer function G(s) of a unity feedback control system is given as,
                          G(s) = [ k(s+2/3)  /  s²(s+2) ]
From the root locus, it can be inferred that when k tends to positive infinity,
A. three roots with nearly equal real parts exist on the left half of the s-plane
B. one real root is found on the right half of the s-plane
C. the root loci cross the jω axis for a finite value of k; k≠0
D. three real roots are found on the right half of the s-plane

Ans:A

[3] Given that

then the value of A³ is  [GATE2012]

        a. 15A+12I

        b. 19A+30I

        c. 17A+15I

        d. 17A+21I

Ans:B

[4] The matrix [A]=
                                





is decomposed into a product of a lower triangular matrix [L] and an upper triangular matrix [U]. The properly decomposed[L] and [U] matrices respectively are............The options A,B,C,D are given below.

Ans: none of the above

[5] The input x(t) of a system are related as y(t) =  ∫^t_-∞ x(τ)cos(3τ)dτ. The system is [GATE2012]

       a. time-invariant and stable

       b. stable and not time-invariant

       c. time-invariant  and not stable 

       d. not time-invariant and not stable

Ans: B

 
[6]The feedback system shown below oscillates at 2 rad/s when [GATE2012]

       a. k=2 and a=0.75

       b. k=3 and a=0.75

       c. k=4 and a=0.5

       d. k=2 and a=0.5

Ans: A

 
[7] The Fourier transform of a signal h(t) is H(jω) = (2cosω)(sin2ω)/ω. The value of h(0) is [GATE2012]

         a. 1/4

         b. 1/2

         c. 1

         d. 2

Ans: C

 
[8] The state variable description of an LTI system is given by

where y is the output and u is the input.The system is controllable for, [GATE2012]

        a. a1≠0,a2=0,a3≠0

        b. a1=0,a2=0,a3≠0

        c. a1=0,a2=0,a3=0

        d. a1≠0,a2≠0,a3=0

Ans:D

[9] The state transition diagram for the logic circuit shown is  [GATE2012]

Ans: D

[10] Given that

then the value of A³ is  [GATE2012]

        a. 15A+12I

        b. 19A+30I

        c. 17A+15I

        d. 17A+21I

Ans: B