Control System: Part-3 Objective Questions with Answers

Control System: Part-3 Objective Questions with Answers

CONTROL SYSTEM OBJECTIVE QUESTIONS FROM COMPETITIVE EXAMS (GATE, IES)

[1]The first two rows of Routh’s tabulation of a third order equation are as follows.
                                    s³  2  2 
                                    s²  4  4 

This means there are [GATE 2009]

A.Two roots at s =± j and one root in right half s-plane

B.Two roots at s =± j2 and one root in left half s- plane

C.Two roots at s = ±j2 and one root in right half s-plane

D.Two  roots at s =± j and one root in left half s-plane

Ans:D

[2]The asymptotic approximation of the log magnitude vs frequency plot of a system

 containing only real poles and zeros is shown. Its transfer function is [GATE 2009]

A.[10(s+5)]/[s(s+2)(s+25)]
B.[1000(s+5)]/[s²(s+2)(s+25)]
C.[100(s+5)]/[s(s+2)(s+25)]
D.[80(s+5)]/[s²(s+2)(s+25)]

Ans:B

 

[3]The trace and determinant of a 2x2 matrix are known to be -2 and -35 respectively. 

Its eigen values are [GATE 2009]

A.-30 and -5

B.-37 and -1

C.-7 and 5

D.17.5 and -2

Ans:C

 
[4]A  Linear Time Invariant system with an impulse response h(t) produces output 

y(t) when input x(t) is applied. When the input x(t-τ) is applied to a system with 

impulse response h(t-τ), the output will be [GATE 2009]

A.y(t)
B.y(2(t-τ))
C.y(t-τ)
D.y(t-2τ)

Ans:D

 

[5]For the Y-bus matrix of a 4-bus system given in per unit, the buses having shunt

 elements are [GATE 2009]

A.  3 and 4 

B.  2 and 3

C.  1 and 2

D.  1,2 and 4

Ans:C

 
[6]The unit step response of a unity feedback system with open loop transfer

 function G(s) = K / ((s+1)(s +2)) is shown in the figure. The value of K is

 [GATE 2009]

A.  0.5 

B.  2

C.  4

D.  6

Ans: D

 
[7 ] For the driving point impedance function, Z(s)=[as2+7s+3]/[s2+3s+b], the circuit realization 

is shown below. The values of 'a' and 'b' respectively are [IES2010]

A. 4 and 5
B. 2 and 5

C. 2 and 1
D. 2 and 3

 
[8] For the following driving point impedance functions, which of the following 

statements is true? [IES2010]

Z1(s)=(s+2)/(s2+3s+5)

Z2(s)=(s+2)/(s2+5)

Z3(s)=(s+2)/(s2+2s+1)

Z4(s)=(s+2)(s+4)/(s+1)(s+3)

A. Z1 is not positive real

B. Z1 is positive real

C. Z3 is positive real

D. Z4 is positive real

Ans: D

 

[9] The steady state error of a unity feedback linear system for a unit step input is 0.1. The 

steady state error of the same system, for a pulse input r(t) having a magnitude of 10 and a 

duration of one second, as shown in the figure is [GATE2011]

A. 0
B. 0.1
C. 1
D. 10

Ans:A

 

[10] A point z has been plotted in the complex plane, as shown in figure below [GATE2011]

The plot of the complex number y=1/z is...........The options A,B,C,D are given below.

Ans:D