9294 + Mcqs in Electronics and Communication Engineering Page 129 McqOptions

6401.	The polar plot of transport lag is a unit circle.
A.	True
B.	False
Answer» B. False

Discussion

6402.	For the signal flow graph of the given figure consider the following statements It has three forward pathsIt has three individual loopsIt has two non touching loops Out of above the correct statements are
A.	1, 2, 3
B.	1, 2
C.	2, 3
D.	1, 3
Answer» E.

Discussion

6403.	For the transport lag G(j ) = e-j T, the polar plot is
A.	a semi circle
B.	a circle
C.	a unit circle
D.	none of the above
Answer» D. none of the above

Discussion

6404.	Assertion (A): When the performance of a stable second order system is improved by a PID controller, the system may become unstable.Reason (R): PID controller increases the order of the system to 3.
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

6405.	The root locus branches
A.	start from open loop poles and terminate at zeros
B.	start from open loop zeros and terminate at poles
C.	may start from pole or zero and terminate at another pole or zero
D.	none of the above
Answer» B. start from open loop zeros and terminate at poles

Discussion

6406.	Consider the following statements: The positiveness of coefficients of characteristic equation is necessary as well as sufficient condition for stability of first and second order systems.The positiveness of coefficients of characteristic equation ensures negativeness of real roots but is not sufficient condition for stability of third and higher order systems. Out of above statements:
A.	only 1 is correct
B.	both 1 and 2 are correct
C.	only 2 is correct
D.	both are wrong
Answer» C. only 2 is correct

Discussion

6407.	In force voltage analogy, displacement is analogous to
A.	current
B.	voltage
C.	charge
D.	none of the above
Answer» D. none of the above

Discussion

6408.	For the system with , the maximum resonance peak is
A.	4
B.	4/3
C.	2
D.	2/
E.	<span class="root">3</span>
Answer» E. <span class="root">3</span>

Discussion

6409.	M circles are symmetrical with respect to real axis.
A.	True
B.	False
Answer» B. False

Discussion

6410.	Assertion (A): The time response, usually, is slower with lag compensation. Reason (R): The natural undamped frequency and bandwidth are increased.
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

6411.	For a factor the log
A.	is a straight line with slope 20 dB/decade
B.	is a straight line with slope 0 dB/decade
C.	is a straight line with slope - 20 dB/decade
D.	is a straight line with slope - 40 dB/decade
Answer» E.

Discussion

6412.	The number of stator field windings in an ac tachometer are
A.	1
B.	2
C.	3
D.	4
Answer» C. 3

Discussion

6413.	The radius of constant N circle for N = 1 is
A.	2
B.	<span class="root">2</span>
C.	1
D.	<img src="/_files/images/electronics-and-communication-engineering/automatic-control-systems/26-243-3.png">
Answer» E.

Discussion

6414.	In using Nyquist stability criterion it is not necessary to determine closed loop poles.
A.	True
B.	False
Answer» B. False

Discussion

6415.	A compensator has its pole and zero as shown in the given figure
A.	lag compensator
B.	lead compensator
C.	lead-lag compensator
D.	series compensator
Answer» C. lead-lag compensator

Discussion

6416.	For a stable system having two or more gain crossover frequencies the phase margin is measured
A.	at lowest gain crossover frequency
B.	at highest gain crossover frequency
C.	at the gain crossover frequencies
D.	none of the above
Answer» C. at the gain crossover frequencies

Discussion

6417.	In a second order system, peak overshoot is independent of
A.	damping factor
B.	natural frequency
C.	both damping factor and natural frequency
D.	neither damping factor nor natural frequency
Answer» C. both damping factor and natural frequency

Discussion

6418.	Nyquist plot provides information about absolute stability as well as relative stability.
A.	True
B.	False
Answer» B. False

Discussion

6419.	Power handling capacity of wire wound potentiometer used in control systems is about
A.	0.1 W
B.	5 W
C.	25 W
D.	100 W
Answer» C. 25 W

Discussion

6420.	A unity feedback system has . If input r(t) = 1 + 2t + t3, the steady error is
A.	zero
B.	0.4
C.	4
D.	infinity
Answer» E.

Discussion

6421.	In terms of and n the settling time (5% criterion) of a second order system for a step input, is equal to
A.	<img src="/_files/images/electronics-and-communication-engineering/automatic-control-systems/22-190-1.png">
B.	<img src="/_files/images/electronics-and-communication-engineering/automatic-control-systems/22-190-2.png">
C.	<img src="/_files/images/electronics-and-communication-engineering/automatic-control-systems/22-190-3.png">
D.	<img src="/_files/images/electronics-and-communication-engineering/automatic-control-systems/22-190-4.png">
Answer» D. <img src="/_files/images/electronics-and-communication-engineering/automatic-control-systems/22-190-4.png">

Discussion

6422.	In the given figure the number of combinations of three non touching loops is
A.	0
B.	1
C.	2
D.	3
Answer» B. 1

Discussion

6423.	In log magnitude Bode diagram the slope of high frequency asymptote of (1 + j T) is
A.	20 dB per decade
B.	10 dB per decade
C.	20 dB per octave
D.	10 dB per octave
Answer» B. 10 dB per decade

Discussion

6424.	Assertion (A): The root locus of a control system is symmetrical about real axis.Reason (R): For all polynomials with real coefficients, complex poles always occur in conjugate pairs.
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

6425.	For the given figure, the transfer function X(s)/P(s) =
A.	<img src="/_files/images/electronics-and-communication-engineering/automatic-control-systems/13-48-1.png">
B.	<img src="/_files/images/electronics-and-communication-engineering/automatic-control-systems/13-48-2.png">
C.	<img src="/_files/images/electronics-and-communication-engineering/automatic-control-systems/13-48-3.png">
D.	<img src="/_files/images/electronics-and-communication-engineering/automatic-control-systems/13-48-4.png">
Answer» C. <img src="/_files/images/electronics-and-communication-engineering/automatic-control-systems/13-48-3.png">

Discussion

6426.	In the given figure shows a root locus plot. Consider the following statements for this plot The open loop system is a second order systemThe system is overdamped for K > 1The system is stable for all values of K Which of the above statements are correct?
A.	1, 2, 3
B.	1, 3
C.	2, 3
D.	1, 2
Answer» C. 2, 3

Discussion

6427.	For the factor the corner frequency is
A.	0.5 rad/sec
B.	1 rad/sec
C.	2 rad/sec
D.	4 rad/sec
Answer» B. 1 rad/sec

Discussion

6428.	For a second order system, the position of poles is shown in the given figure. This system is
A.	undamped
B.	overdamped
C.	underdamped
D.	critically damped
Answer» D. critically damped

Discussion

6429.	A lag compensator provides attenuation in
A.	very low frequency range
B.	low frequency range
C.	high frequency range
D.	none of the above
Answer» D. none of the above

Discussion

6430.	A stepper motor is essentially
A.	a synchronous motor
B.	induction motor
C.	dc motor
D.	either (b) or (c)
Answer» B. induction motor

Discussion

6431.	For the characteristic equation s5 + s4 + 2s3 + 2s2 + 3s + 15 = 0, the number of roots in left half s plane are
A.	1
B.	2
C.	3
D.	5
Answer» D. 5

Discussion

6432.	The angular location of poles depends on
A.	undamped natural frequency
B.	damping ratio
C.	both (a) and (b)
D.	neither (a) nor (b)
Answer» C. both (a) and (b)

Discussion

6433.	If Z is the number of zeros of 1 + G(s) H(s) in the right half s plane. N is the number of clockwise encircle elements of (-1 + jo) point. P is the number of poles of G(s) H(s) in right half s plane. The Nyquist stability criterion can be expressed as
A.	Z = N + P
B.	Z = P/N
C.	Z = N - P
D.	Z = PN
Answer» B. Z = P/N

Discussion

6434.	The given figure shows a control system. The maximum value of gain for which the system is stable is
A.	<span class="root">3</span>
B.	3
C.	4
D.	5
Answer» C. 4

Discussion

6435.	For stable network the real parts of poles and zeros of driving point functions must be
A.	negative
B.	negative or zero
C.	zero
D.	positive
Answer» C. zero

Discussion

6436.	A compensating network has . If it is a phase lag circuit the value of a should be
A.	0
B.	between 0 and 1
C.	1
D.	more than 1
Answer» C. 1

Discussion

6437.	Consider the following expressions which indicate the step or impulse response of an initially relaxed system [5 - 4 e-2t] u(t)[e-2t + 5] u(t)d(t) + 8 e-2t u(t)d(t) + 4 e-2t u(t) Those which correspond to the step and impulse response of the same system include
A.	1 and 3
B.	1 and 4
C.	2 and 4
D.	2 and 3
Answer» B. 1 and 4

Discussion

6438.	The given figure shows a constant current source driving a parallel RC circuit. It is equivalent to
A.	a lag network
B.	a lead network
C.	a lag-lead network
D.	either (a) or (b)
Answer» B. a lead network

Discussion

6439.	For the transport lag G(j ) = e-j T, the phase angle
A.	is constant
B.	varies linearly with frequency
C.	varies linearly with low frequencies only
D.	values as per square law
Answer» C. varies linearly with low frequencies only

Discussion

6440.	In classical analogue, torque is analogous to
A.	current
B.	voltage
C.	charge
D.	voltage gradient
Answer» C. charge

Discussion

6441.	The pole zero plot of the given figure is for
A.	non-minimum phase function
B.	minimum phase function
C.	all pass function
D.	either (b) or (c)
Answer» B. minimum phase function

Discussion

6442.	Coulomb friction is
A.	the force of sliding friction between dry surfaces
B.	the force of friction between moving surfaces separated by viscous fluid
C.	the force required to initiate motion between two contacting surfaces
D.	all of the above
Answer» B. the force of friction between moving surfaces separated by viscous fluid

Discussion

6443.	The given figure shows log magnitude versus plots of a system for different values of gain. For this system
A.	curve 1 shows highest gain margin and curve 2 shows poorest gain margin
B.	gain margins shown by the three curves are equal
C.	curve 1 shows poorest gain margin and curve 3 shows highest gain margin
D.	curve 3 shows poorest gain margin while curve 1 shows highest gain margin
Answer» D. curve 3 shows poorest gain margin while curve 1 shows highest gain margin

Discussion

6444.	The purpose of series quadrature windings in amplidyne is to
A.	neutralize the effect of armature reaction
B.	reduce commutation difficulties
C.	increase the gain
D.	increase response time
Answer» B. reduce commutation difficulties

Discussion

6445.	Assertion (A): Integral control action is sometimes called reset control.Reason (R): Reset rate is expressed as number of repeats per unit time.
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

6446.	Assertion (A): Derivative control action is also called rate control and has an anticipatory character.Reason (R): Derivative control amplifies noise signals.
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

6447.	Assertion (A): When a PID controller is added to a system, the peak overshoot to step input cannot be determined easily.Reason (R): Use of PID controller introduces a zero in the forward path.
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

6448.	For the function G(s) H(s) = the phase cross-over frequency is
A.	0.5 rad/sec
B.	0.707 rad/sec
C.	1.732 rad/sec
D.	2 rad/sec
Answer» C. 1.732 rad/sec

Discussion

6449.	Nyquist stability criterion is based on a theorem from the theory of complex variables.
A.	True
B.	False
Answer» B. False

Discussion

6450.	While forming Routh's array, the situation of a row of zeros indicates that the system
A.	has symmetrically located roots
B.	is not sensitive to variations in gain
C.	is stable
D.	is unstable
Answer» B. is not sensitive to variations in gain

Discussion

Explore topic-wise MCQs in Engineering.

The polar plot of transport lag is a unit circle.

For the signal flow graph of the given figure consider the following statements It has three forward pathsIt has three individual loopsIt has two non touching loops Out of above the correct statements are

For the transport lag G(j ) = e-j T, the polar plot is

Assertion (A): When the performance of a stable second order system is improved by a PID controller, the system may become unstable.Reason (R): PID controller increases the order of the system to 3.

The root locus branches

In force voltage analogy, displacement is analogous to

For the system with , the maximum resonance peak is

M circles are symmetrical with respect to real axis.

Assertion (A): The time response, usually, is slower with lag compensation. Reason (R): The natural undamped frequency and bandwidth are increased.

For a factor the log

The number of stator field windings in an ac tachometer are

The radius of constant N circle for N = 1 is

In using Nyquist stability criterion it is not necessary to determine closed loop poles.

A compensator has its pole and zero as shown in the given figure

For a stable system having two or more gain crossover frequencies the phase margin is measured

In a second order system, peak overshoot is independent of

Nyquist plot provides information about absolute stability as well as relative stability.

Power handling capacity of wire wound potentiometer used in control systems is about

A unity feedback system has . If input r(t) = 1 + 2t + t3, the steady error is

In terms of and n the settling time (5% criterion) of a second order system for a step input, is equal to

In the given figure the number of combinations of three non touching loops is

In log magnitude Bode diagram the slope of high frequency asymptote of (1 + j T) is

Assertion (A): The root locus of a control system is symmetrical about real axis.Reason (R): For all polynomials with real coefficients, complex poles always occur in conjugate pairs.

For the given figure, the transfer function X(s)/P(s) =

In the given figure shows a root locus plot. Consider the following statements for this plot The open loop system is a second order systemThe system is overdamped for K &gt; 1The system is stable for all values of K Which of the above statements are correct?

For the factor the corner frequency is

For a second order system, the position of poles is shown in the given figure. This system is

A lag compensator provides attenuation in

A stepper motor is essentially

For the characteristic equation s5 + s4 + 2s3 + 2s2 + 3s + 15 = 0, the number of roots in left half s plane are

The angular location of poles depends on

If Z is the number of zeros of 1 + G(s) H(s) in the right half s plane. N is the number of clockwise encircle elements of (-1 + jo) point. P is the number of poles of G(s) H(s) in right half s plane. The Nyquist stability criterion can be expressed as

The given figure shows a control system. The maximum value of gain for which the system is stable is

For stable network the real parts of poles and zeros of driving point functions must be

A compensating network has . If it is a phase lag circuit the value of a should be

Consider the following expressions which indicate the step or impulse response of an initially relaxed system [5 - 4 e-2t] u(t)[e-2t + 5] u(t)d(t) + 8 e-2t u(t)d(t) + 4 e-2t u(t) Those which correspond to the step and impulse response of the same system include

The given figure shows a constant current source driving a parallel RC circuit. It is equivalent to

For the transport lag G(j ) = e-j T, the phase angle

In classical analogue, torque is analogous to

The pole zero plot of the given figure is for

Coulomb friction is

The given figure shows log magnitude versus plots of a system for different values of gain. For this system

The purpose of series quadrature windings in amplidyne is to

Assertion (A): Integral control action is sometimes called reset control.Reason (R): Reset rate is expressed as number of repeats per unit time.

Assertion (A): Derivative control action is also called rate control and has an anticipatory character.Reason (R): Derivative control amplifies noise signals.

Assertion (A): When a PID controller is added to a system, the peak overshoot to step input cannot be determined easily.Reason (R): Use of PID controller introduces a zero in the forward path.

For the function G(s) H(s) = the phase cross-over frequency is

Nyquist stability criterion is based on a theorem from the theory of complex variables.

While forming Routh's array, the situation of a row of zeros indicates that the system

In the given figure shows a root locus plot. Consider the following statements for this plot The open loop system is a second order systemThe system is overdamped for K > 1The system is stable for all values of K Which of the above statements are correct?