Code: AE11/ 03-04 Subject: CONTROL ENGINEERING 1 PART – I TYPICAL QUESTIONS & ANSWERS OBJECTIVE TYPE QUESTIONS

Code: AE11/ 03-04 Subject: CONTROL
ENGINEERING 1 PART – I TYPICAL
QUESTIONS & ANSWERS OBJECTIVE
TYPE QUESTIONS

PART – I

TYPICAL QUESTIONS & ANSWERS
OBJECTIVE TYPE QUESTIONS

Each Question carries 2 marks.

Choose the correct or best alternative in the following:


Q.1 The steady-state error of a feedback control system with an acceleration input becomes
finite in a

(A) type 0 system. (B) type 1 system.
(C) type 2 system. (D) type 3 system.

Ans: (C)

Q.2 The Laplace transform of e−2tsin 2ωt is _______.




1

, 2s
(A) (B)

2s
(C) (D)
2 2

(s + 2) + 2ω

Ans: (C)

Q.3 Considering the root locus diagram for a system with
K(s +5)
G(s) = 2, the meeting point of the asymptotes on the real
s(s + 2) (s + 4) (s + 2s + 2) axis occurs at _________.

(A) –1.2 (B) –0.85
(C) –1.05 (D) –0.75

Ans: (D)

Q.4 Figure 1 shows a circuit for which switch S is kept
open for a long time and then closed at t = 0. The
dynamic equation governing the circuit will then
be
___________.

(C) dt i(0)
9i + 4 i dt =180 =15
(A) i(0) =10
di Ans: (C)
12i + 4 =180
(B) dt i(0) = 25 12i + 4 i dt =180
di (D) i(0) =15
9i + 4 =180
Q.5 Considering the unity feedback system of Fig. 2, the
settling time of the resulting second order system for
2% tolerance band will be ________.

(A) 3.33 (B) 4.5
(C) 2.25 (D) 2.84


Ans: (A)
8(s + 3)




2

,Q.6 If for a control system, the Laplace transform of error e(t) is
given as then s (s +10) the steady state value of
the error works out as ______.

(A) 3.6 (B) 1.8
(C) 3.2 (D) 2.4

Ans: (D)

Q.7 The transfer function of the block diagram of Fig.3 is
_________.

G (G + G ) G (G + G )
(A) 21 3
(B) 1 2

1+ G1G 2H + G1G3H 3

1+ G1G 2H +
3
G1G3H
G (G − G ) G (G + G )
12 3 1 2 3




(C) (D)
1+ G1H + G 2H 1+ G1H + G H




Ans: (B)

Q.8 The impulse response of a LTI system is a unit step function,
then the corresponding transfer function is

1 1
(A) (B)
.s 2.

s
(C) 1. (D)
s.

Ans: (A)


3

, Q.9 For a type one system, the steady – state error due to step
input is equal to

(A) infinite. (B) zero.
(C) 0.25. (D) 0.5.

Ans: (B)

Q.10 The equation 2 s4 + s3 + 3 s2 + 5 s +10 = 0 has


(A) one (B) two
(C) three (D) four

roots in the left half of s–plane.

Ans: (B)


Q.11 If the Nyquist plot of the loop transfer function G s H s ( )
( ) of a closed-loop system encloses the (−1, jo) point in
the G s H s( ) ( ) plane, the gain margin of the system is

(A) zero. (B) greater than zero.
(C) less than zero. (D) infinity.

Ans: (C)



Q.12 Consider the function F s ( )= 2 ), where F s( ) is
5

the Laplace transform s
s( + s + 2
of f (t). Limf t( ) is equal to
t→∞



(A) 5. (B) .
(C) zero. (D) infinity.

Ans: (B)

Q.13 The transfer function of a phase-lead controller is given by



4