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BUY PACKAGESolution Report For Control Systems : Adv : Practice Test -
24
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Q. Question Status
No
Q.1
The state equation of an LTI system is given by
The eigen values are
a. –1 and –2
b. 0 and –3
c. 1 and –3
d. 1 and –2
Not Attem pt Correct Ans. a
FAQ? Have any doubt? Solution
Q.2
The offset in proportional controller can be removed by
a. Derivative controller
b. Proportional controller
c. Integral controller
d. None of these
Not Attem pt Correct Ans. c
FAQ? Have any doubt? Solution
Q.3
Which of the following is the open loop transfer function of the root loci
shown in figure?
a.
b.
c.
d.
Not Attem pt Correct Ans. d
FAQ? Have any doubt? Solution
Q.4
A forcing function (t2 – 2t) u(t – 1) is applied to a linear system. The
Laplace transform of the forcing function is
a.
b.
c.
d.
Not Attem pt Correct Ans. d
FAQ? Have any doubt? Solution
Q.5
The pole zero and the Nyquist plot of the loop transfer function G(s)H(s)
of a feedback system is shown below:
For these systems
a. Both open loop and closed loop systems are unstable.
b. Open loop system is stable but closed loop system is unstable.
c. Both open loop and closed loop systems are stable.
d. Open loop system is unstable but closed loop system is stable.
Not Attem pt Correct Ans. b
FAQ? Have any doubt? Solution
Q.6
A unity feedback control system has a forward loop transfer function as
. Its phase value will be zero at frequency . Which one of
the following equations should be satisfied by ?
a.
b.
c.
d.
Not Attem pt Correct Ans. a
FAQ? Have any doubt? Solution
Q.7
For the given feedback system, the forward path does not affect the
system output if KG is
a. Very small
b. One
c. Negative
d. Very large
Not Attem pt Correct Ans. d
FAQ? Have any doubt? Solution
Q.8
Consider the block diagram shown below
The transfer function is:
a.
b.
c.
d.
Not Attem pt Correct Ans. b
FAQ? Have any doubt? Solution
Q.9
If the state transition matrix is φ(t) = , then the state
matrix A is
a.
b.
c.
d.
Not Attem pt Correct Ans. d
FAQ? Have any doubt? Solution
Q.10
A compensating network has its transfer function
The maximum phase occurs at a frequency of ________ rad/sec.
Not Attem pt Correct Ans. 20
FAQ? Have any doubt? Solution
Q.11
The open loop transfer function of a unity feedback control system is
given below
The value of system gain ‘K’ for system to be critically damped is
________
Not Attem pt Correct Ans. 100
FAQ? Have any doubt? Solution
Q.12
A control system with certain excitation is governed by the following
mathematical equation
where y is the input and x is the output
The sum of the time constants of the response of the system is _______
sec.
Not Attem pt Correct Ans. 9
FAQ? Have any doubt? Solution
Q.13
An Integrator has transfer function given by T(s) = . If it is required
to have gain magnitude unity at frequency ω = 250 rad/sec then, the gain
that must be placed in cascade will be ______.
Not Attem pt Correct Ans. 12.5 (12.0 - 13.0)
FAQ? Have any doubt? Solution
Q.14
The open loop transfer function of a unity feedback system is
The value of ‘K’ for which the closed loop pole of the system will be
located at s = – 6 is _____.
Not Attem pt Correct Ans. 278.4 (278.0 - 279.0)
FAQ? Have any doubt? Solution
Q.15
A unity feedback system has an open loop transfer function
The phase cross over frequency is ______ rad/sec
Not Attem pt Correct Ans. 14.14 (14.00 - 14.50)
FAQ? Have any doubt? Solution
Q.16
The frequency response of an underdamped second order system is
shown below.
The appropriate damping ratio ξ is ______.
Not Attem pt Correct Ans. 0.404 (0.39 - 0.41)
FAQ? Have any doubt? Solution
Q.17
A unity feedback closed loop control system has
Its root locus technique will give
1. Stable system for K > –4
2. GM = 1
3. PM = 180°
The correct statements are
a. 2 and 3
b. 1 and 3
c. 1 and 2
d. All
Not Attem pt Correct Ans. b
FAQ? Have any doubt? Solution
Q.18
The closed loop transfer function of a system is
The system is said to be
a. Unstable with a pair of complex conjugate poles on imaginary axis
b. Unstable with two pair of complex conjugate poles on imaginary axis
c. Marginal stable with all poles on imaginary axis
d. Marginal stable with a pair of complex conjugate poles on imaginary
axis
Not Attem pt Correct Ans. b
FAQ? Have any doubt? Solution
Q.19
Consider a control system having open loop transfer function
If all the finite poles has positive real part, then the polar plot of the
system will be
a.
b.
c.
d.
Not Attem pt Correct Ans. a
FAQ? Have any doubt? Solution
Q.20
The transfer function of a phase lead network, as shown in the figure
below is
The values of R1 and R2 are respectively
a. 300 kΩ and 300 kΩ
b. 300 kΩ and 400 kΩ
c. 400 kΩ and 300 kΩ
d. 400 kΩ and 400 kΩ
Not Attem pt Correct Ans. b
FAQ? Have any doubt? Solution
Q.21
A feedback system is described by
The phase cross over frequency and the corresponding gain margin is
a. 500 rad/sec and 10.99 dB
b. 22.36 rad/sec and –10.49 dB
c. 22.36 rad/sec and 20.42 dB
d. 500 rad/sec and –20.42 dB
Not Attem pt Correct Ans. c
FAQ? Have any doubt? Solution
Q.22
The state model of a system is given as
The above system is
a. A non minimum phase system.
b. A minimum phase system.
c. An all pass system.
d. None of the above
Not Attem pt Correct Ans. a
FAQ? Have any doubt? Solution
Q.23
For the system dynamics described by differential equation
the transfer function of the system represented in
controllable canonical form is C[sI – A]–1 B. The matrix A would be
a.
b.
c.
d.
Not Attem pt Correct Ans. c
FAQ? Have any doubt? Solution
Q.24
The transfer function of a PID controller is given by G(s) =
, as ω tends to zero
a. magnitude of G(jω) tends to zero and phase angle of G(jω) tends to
infinity
b. magnitude of G(jω) tends to infinity and phase angle of G(jω) tends to
zero
c. magnitude of G(jω) tends to infinity and phase angle of G(jω) tends
to +90°
d. magnitude of G(jω) tends to zero and phase angle of G(jω) tends to
+90°
Not Attem pt Correct Ans. c
FAQ? Have any doubt? Solution
Q.25
The response of a system to a unit ramp input is .
Which one of the following is the unit impulse response of the system?
a. 1 – e– 4t
b. 2(1 – e– 4t)
c. e– 4t
d. 2 e– 4t
Not Attem pt Correct Ans. d
FAQ? Have any doubt? Solution
Q.26
For the given open loop transfer function
The slope of the line between frequency of 4 rad/sec and 10 rad/sec is
_________ dB/decade.
Not Attem pt Correct Ans. -80
FAQ? Have any doubt? Solution
Q.27
For open loop transfer function
The gain ‘K’ at break point will be _______ .
Not Attem pt Correct Ans. 0.20 (0.18 - 0.22)
FAQ? Have any doubt? Solution
Q.28
A feedback control system has an open loop transfer function.
The maximum value of ‘K’ for closed loop system stability is _________
Not Attem pt Correct Ans. 0.4
FAQ? Have any doubt? Solution
Q.29
A feed back control system is shown below
If the forward path gain is 400 and feedback gain is 0.05. The percentage
change in closed loop gain for 10% change in G is ________
Not Attem pt Correct Ans. 0.476 (0.450 - 0.490)
FAQ? Have any doubt? Solution
Q.30
The transfer function of a unity feedback (type-1) second order system
has a pole at (s = –2). The nature of gain K is such that the damping ratio
is 0.4. The steady state error for r(t) = 4t is _____.
Not Attem pt Correct Ans. 1.28 (1.25 - 1.30)
FAQ? Have any doubt? Solution
Q.31
A second order unity feedback control system requires 0.52 seconds to
reach its peak value while subjected to the step input. If the settling time
of the response for 2% tolerance band is 1.05 seconds. The resonant
frequency of the system will be _______ rad/sec.
Not Attem pt Correct Ans. 4.676 (4.500 - 4.700)
FAQ? Have any doubt? Solution
Q.32
A second order position control system has open loop transfer function
Where ‘A’ is the amplifier gain. The value of A so that steady state error
shall not exceed 2° (for r(t) = π/4 rad) is _____.
Not Attem pt Correct Ans. 3.44 (3.30 - 3.50)
FAQ? Have any doubt? Solution
Q.33
A feedback system employing output rate damping is shown below
In the absence of derivative feedback, the rise time for the system
response is _______ sec.
Not Attem pt Correct Ans. 0.356 (0.300 - 0.400)
FAQ? Have any doubt? Solution
