Explore topic-wise MCQs in Automatic Control Systems.

This section includes 25 Mcqs, each offering curated multiple-choice questions to sharpen your Automatic Control Systems knowledge and support exam preparation. Choose a topic below to get started.

1.

The phase angle curve of G(j ) H(j ) can be drawn

A. by adding the phase angle curves of individual factors
B. by subtracting the phase angle curves of individual factors
C. by multiplying the phase angle curves of individual factors
D. by dividing the phase angle curves of individual factors
Answer» B. by subtracting the phase angle curves of individual factors
Discussion
2.

Which of the following rotors are used in two phase ac servomotor? 1.Solid iron rotor 2.Squirrel cage rotor 3.Drag cup rotor Of the above the correct ones are

A. 1, 2, 3
B. 1, 2
C. 2, 3
D. 1, 3
Answer» D. 1, 3
Discussion
3.

If the Nyquist plot does not encircle the (-1 + j0) point the system is always stable.

A. True
B. False
Answer» C.
Discussion
4.

Assertion (A): When the phase margin of a control system is improved using a lead network, noise transmission increases. Reason (R): Phase lead compensation increases bandwidth.

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» B. Both A and R are correct but R is not correct explanation of A
Discussion
5.

Assertion (A): A slight change in pole-zero configuration can cause only minor changes in root locus configuration. Reason (R): Asymptotes show the behaviour of root loci for |s| >> 1

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» E.
Discussion
6.

The constant magnitude of G(s) plane are

A. a family of straight horizontal lines
B. a family of straight inclined lines with positive slope
C. a family of straight inclined lines with negative slope
D. a family of circles
Answer» E.
Discussion
7.

Assertion (A): Integration in time domain is converted into division in s domain Reason (R):

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» C. A is correct but R is wrong
Discussion
8.

Assertion (A): In an automobile the amount of fuel admitted to the engine is adjusted as per the difference between desired and actual speed. Reason (R): The control signal is the amount of fuel to be admitted to the engine.

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» C. A is correct but R is wrong
Discussion
9.

ssertion (A): The steady state response, of a stable, linear, time invariant system, to sinusoidal input depends on initial conditions. Reason (R): Frequency response, in steady state, is obtained by replacing s in the transfer function by j

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» E.
Discussion
10.

A system has its two poles on the negative real axis and one pair of poles lies on j axis. The system is

A. stable
B. unstable
C. limitedly stable
D. either (a) or (c)
Answer» D. either (a) or (c)
Discussion
11.

Assertion (A): If minimum phase system has a gain margin of 8 dB and phase margin of 21 , the system is stable. Reason (R): For a minimum phase system both GM and PM must be positive for the system to be stable.

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» B. Both A and R are correct but R is not correct explanation of A
Discussion
12.

Assertion (A): In root locus the breakaway and break in points either lie on real axis or occur in complex conjugate pairs. Reason (R): All root locus asymptotes intersect on real axis.

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» C. A is correct but R is wrong
Discussion
13.

For 0 < M>

A. True
B. False
Answer» B. False
Discussion
14.

Which of the following can act as error detecting devices 1.a pair of potentiometers 2.a pair of synchros 3.a differential transformer 4.a metadyne 5.a control transformer Select the answer using the following codes:

A. 1, 2, 5
B. 2, 3, 4, 5
C. 1, 3, 4, 5
D. 1, 2, 3, 4
Answer» B. 2, 3, 4, 5
Discussion
15.

For any test point s on the real axis, the sum of angular contributions of the complex conjugate poles is

A. 90
B. 180
C. 270
D. 360
Answer» E.
Discussion
16.

Bode magnitude plot is drawn between

A. magnitude of network function and
B. dB magnitude and log
C. dB magnitude and
D. log
E. (magnitude) and log
Answer» C. dB magnitude and
Discussion
17.

For type 2 system, the magnitude and phase angle of the term (j )2 in the denominator, at = 0, are respectively

A. 0 and - 90
B. 0 and + 90
C. infinity and - 180
D. infinity and + 180
Answer» D. infinity and + 180
Discussion
18.

For the transport lag G(j ) = e-j T, the magnitude is always equal to

A. 1
B. 10
C. 0.5
Answer» C. 0.5
Discussion
19.

Assertion (A): Potentiometers can not be used as error detectors in position control systems. Reason (R): The resolution of a potentiometer places an upper limit on its accuracy

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» E.
Discussion
20.

Which of the following can be used as a rotating amplifier in a control system? 1.Amplidyne 2.Separately excited dc generator 3.Synchro 4.Self excited dc generator Select the answer from the following codes:

A. 3 and 4
B. 1 and 2
C. 1, 2 and 3
D. all
Answer» C. 1, 2 and 3
Discussion
21.

The maximum shift which can be provided by a lead compensator with transfer function is

A. 15
B. 30
C. 45
D. 60
Answer» C. 45
Discussion
22.

In a second order system, the time constant t of exponential envelopes depends

A. only on damping factor
B. only on natural frequency
C. both on damping factor and natural frequency
D. neither on damping factor nor on natural frequency
Answer» D. neither on damping factor nor on natural frequency
Discussion
23.

The slope of log-magnitude asymptote changes by - 40 dB/ decade at a frequency 1. This means that

A. a double pole is present
B. a pair of complex conjugate poles is present
C. either a double pole or a pair of complex conjugate poles is present
D. a pole or zero at origin is present
Answer» D. a pole or zero at origin is present
Discussion
24.

Assertion (A): When performance specifications are given in term of transient response characteristics, root locus method is a suitable method. Reason (R): When performance specifications in terms of state variables are given, modern control methods can be used.

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» C. A is correct but R is wrong
Discussion
25.

Assertion (A): If points at infinity are included, G(s) has same number of poles and zeros. Reason (R): The function has a zero at s = - 2.

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» C. A is correct but R is wrong
Discussion