Explore topic-wise MCQs in Control System.

This section includes 180 Mcqs, each offering curated multiple-choice questions to sharpen your Control System knowledge and support exam preparation. Choose a topic below to get started.

151.

Consider a unity feedback control system with open-loop transfer function

A. zero
B. K
C. 1/ K
D.
Answer» B. K
Discussion
152.

A system is represented by

A. t u(t)
B. 2t u (t)
C. 3t u (t)
D. 4t u (t)
Answer» C. 3t u (t)
Discussion
153.

What will be the closed loop transfer function of a unity feedback control system whose step response is given by

A. <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>100 K</center></td><td rowspan="2"> </td></tr><tr><td style="text-align: center;">s<sup>2</sup> + 16s + 100</td></tr></table>
B. <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>10 K</center></td><td rowspan="2"> </td></tr><tr><td style="text-align: center;">s<sup>2</sup> + 16s + 100</td></tr></table>
C. <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>K</center></td><td rowspan="2"> </td></tr><tr><td style="text-align: center;">s<sup>2</sup> + 16s + 100</td></tr></table>
D. <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>10 K</center></td><td rowspan="2"> </td></tr><tr><td style="text-align: center;">s<sup>2</sup> + 8s + 10</td></tr></table>
Answer» B. <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>10 K</center></td><td rowspan="2"> </td></tr><tr><td style="text-align: center;">s<sup>2</sup> + 16s + 100</td></tr></table>
Discussion
154.

A unity feedback control system has a forward path transfer function equal to

A. 0 sec
B. 0.56 sec
C. 5.6 sec
D. infinity
Answer» E.
Discussion
155.

Consider a system shown in the given figure

A. 1 + t
B. 1 t
C. 1 + 2t
D. 1 2t
Answer» D. 1 2t
Discussion
156.

In the derivative error compensation, damping

A. decreases and settling time decreases
B. increases and settling time increases
C. decreases and settling time increases
D. increases and settling time decreases
Answer» E.
Discussion
157.

The forward-path transfer function of a unity feedback system is

A. K > -1
B. <table><tr><td rowspan="2">K &lt; </td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>3</center></td><td rowspan="2"></td></tr><tr><td style="text-align: center;">4</td></tr></table>
C. <table><tr><td rowspan="2">-1 &lt; K &lt; </td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>3</center></td><td rowspan="2"></td></tr><tr><td style="text-align: center;">4</td></tr></table>
D. marginal stable
Answer» E.
Discussion
158.

The Nyquist plot of a loop transfer funct ion G(j ) H(j ) of a system encloses the ( 1, j0) point. The gain margin of the system is

A. less than zero
B. zero
C. greater than zero
D. infinity
Answer» B. zero
Discussion
159.

Consider the following statements regarding timedomain analysis of a control system :

A. 1 and 2 are correct
B. 1 and 3 are correct
C. 2 and 3 are correct
D. 1, 2 and 3 are correct
Answer» C. 2 and 3 are correct
Discussion
160.

The open-loop transfer function of a unity feedback control system is

A. T > 0
B. 0 < T < 3
C. T > 5
D. 3 < T < 4
Answer» D. 3 < T < 4
Discussion
161.

Consider the following polynomials :

A. 1 and 3
B. 2 and 3
C. 1 and 2
D. 1, 2 and 3
Answer» D. 1, 2 and 3
Discussion
162.

The number of roots of s

A. zero
B. one
C. two
D. three
Answer» B. one
Discussion
163.

The close-loop transfer function of a control system is given by

A. <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>1</center></td><td rowspan="2">cos t</td></tr><tr><td style="text-align: center;"> <span style=" text-decoration: overline;">2</span></td></tr></table>
B. 1
C. <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>1</center></td><td rowspan="2">sin t</td></tr><tr><td style="text-align: center;"> <span style=" text-decoration: overline;">2</span></td></tr></table>
D. <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>1</center></td><td rowspan="2">sin </td><td rowspan="2"><img src="https://www.indiabix.com/_files/images/data-interpretation/common/15-sym-oparen-h1.gif"></td><td rowspan="2">t - </td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center> </center></td><td rowspan="2"><img src="https://www.indiabix.com/_files/images/data-interpretation/common/15-sym-cparen-h1.gif"></td></tr><tr><td style="text-align: center;"> <span style=" text-decoration: overline;">2</span></td><td style="text-align: center;">4</td></tr></table>
Answer» E.
Discussion
164.

The phase margin of a system with the open-loop transfer function

A. 0
B. 63.4
C. 90
D.
Answer» E.
Discussion
165.

The position and velocity error coefficients for the system of transfer function

A. zero and zero
B. zero and infinity
C. 50 and zero
D. 50 and infinity
Answer» D. 50 and infinity
Discussion
166.

For a feedback control system of type 2, the steady state error for a ramp input is

A. infinite
B. constant
C. zero
D. indeterminate
Answer» D. indeterminate
Discussion
167.

The system with the open loop transfer function G(s) H(s) = 1 has a gain margin of s(s2 + s + 1)

A. 6 dB
B. 0 dB
C. 3.5 dB
D. 6 dB
Answer» C. 3.5 dB
Discussion
168.

An electromechanical closed-loop control system has the following characteristic equation :

A. K = 0.528
B. K = 2
C. K = 0
D. K = 2.58
Answer» B. K = 2
Discussion
169.

None of the poles of a linear control system lie in the right half of s-plane. For a bounded input, the output of this system

A. is always bounded
B. could be unbounded
C. always tends to zero
D. none of these
Answer» C. always tends to zero
Discussion
170.

Consider a feedback control system with loop transfer function

A. zero
B. one
C. two
D. three
Answer» C. two
Discussion
171.

In the Bode-plot of a unit y feedback cont rol system, the value of phase of G (j ) at the gain cross over frequency is 125 . The phase margin of the system is

A. 125
B. 55
C. 55
D. 125
Answer» D. 125
Discussion
172.

The characteristic equation of a closed-loop system is given by

A. 0 < K < 10
B. K > 10
C. < K <
D. 0 < K < 20
Answer» B. K > 10
Discussion
173.

A linear discrete-time system has t he characteristic equation, z

A. is stable
B. is marginally stable
C. is unstable
D. stability cannot be assessed from the given information
Answer» B. is marginally stable
Discussion
174.

The open loop transfer function of a system is

A. <img src="http://images.interviewmania.com/wp-content/uploads/2019/11/as-897.jpg">
B. <img src="http://images.interviewmania.com/wp-content/uploads/2019/11/as-898.jpg">
C. <img src="http://images.interviewmania.com/wp-content/uploads/2019/11/as-899.jpg">
D. <img src="http://images.interviewmania.com/wp-content/uploads/2019/11/as-900.jpg">
Answer» C. <img src="http://images.interviewmania.com/wp-content/uploads/2019/11/as-899.jpg">
Discussion
175.

A system has a complex conjugate root pair of multiplicity two or more in its characteristic equation. The impulse response of the system will be

A. a sinusoidal oscillation which decays exponentially; the system is therefore stable.
B. a sinusoidal oscillation with time multiplier; the system is therefore unstable.
C. a sinusoidal oscillation which rises exponentially with time; the system is therefore unstable.
D. a dc term and harmonic oscillation; the system therefore becomes limitingly stable.
Answer» C. a sinusoidal oscillation which rises exponentially with time; the system is therefore unstable.
Discussion
176.

The unstable system is

A. <table><tr><td rowspan="2">G(s) H(s) = </td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>K</center></td><td rowspan="2"> ; K &gt; 0</td></tr><tr><td style="text-align: center;">(T<sub>1</sub>s + 1)(T<sub>2</sub>s + 1)</td></tr></table>
B. <table><tr><td rowspan="2">G(s) H(s) = </td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>K(s + 1)</center></td><td rowspan="2"> ; K &gt; 91</td></tr><tr><td style="text-align: center;">s<sup>2</sup>(s + 4)(s + 5)</td></tr></table>
C. <table><tr><td rowspan="2">G(s) H(s) = </td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>K(s + 2)</center></td><td rowspan="2"> ; K &gt; 2</td></tr><tr><td style="text-align: center;">(s + 1)(s - 3)</td></tr></table>
D. <table><tr><td rowspan="2">G(s) H(s) = </td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>K</center></td><td rowspan="2"> ; -1 &lt; K &lt; 2</td></tr><tr><td style="text-align: center;">(Ts + 1)<sup>3</sup></td></tr></table>
Answer» C. <table><tr><td rowspan="2">G(s) H(s) = </td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>K(s + 2)</center></td><td rowspan="2"> ; K &gt; 2</td></tr><tr><td style="text-align: center;">(s + 1)(s - 3)</td></tr></table>
Discussion
177.

The feedback system with characteristic equation

A. stable for all value of K
B. stable for positive value of K
C. stable for > K > 7.0
D. unstable for all values of K
Answer» E.
Discussion
178.

The number of roots of the equation 2s

A. zero
B. one
C. two
D. three
Answer» D. three
Discussion
179.

What is the unit step response of a unity feedback control system having forward path transfer

A. Overdamped
B. Critically damped
C. Underdamped
D. Undamped oscillatory
Answer» E.
Discussion
180.

The transfer function of the system described by

A. <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>(s + 2)</center></td><td rowspan="2"> </td></tr><tr><td style="text-align: center;">(s<sup>2</sup> + s)</td></tr></table>
B. <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>(s + 1)</center></td><td rowspan="2"> </td></tr><tr><td style="text-align: center;">(s<sup>2</sup> + s)</td></tr></table>
C. <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>s</center></td><td rowspan="2"> </td></tr><tr><td style="text-align: center;">(s<sup>2</sup> + s)</td></tr></table>
D. <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>2s</center></td><td rowspan="2"> </td></tr><tr><td style="text-align: center;">(s<sup>2</sup> + s)</td></tr></table>
Answer» B. <table><tr><td rowspan="2"></td><td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center>(s + 1)</center></td><td rowspan="2"> </td></tr><tr><td style="text-align: center;">(s<sup>2</sup> + s)</td></tr></table>
Discussion