List Of Objective Questions On Control Systems
1.A good control system has all the following features except
good stability
slow response
good accuracy
sufficient power handling capacity
ANSWER : : slow response
2.In open loop system
the control action depends on the size of the system
the control action depends on system variables
the control action depends on the input signal
the control action is independent of the output
ANSWER : : the control action is independent of the output
3.The initial response when tne output is not equal to input is called
Transient response
Error response
Dynamic response
Either of the above
ANSWER : : Transient response
4.For open control system which of the following statements is incorrect ?
Less expensive
Recalibration is not required for maintaining the required quality of the output
Construction is simple and maintenance easy
Errors are caused by disturbances
ANSWER : : Recalibration is not required for maintaining the required quality of the output
5.Which of the following statements is not necessarily correct for open control system ?
Input command is the sole factor responsible for providing the control action
Presence of non-linearities causes malfunctioning
Less expensive
Generally free from problems of non-linearities
ANSWER : : Presence of non-linearities causes malfunctioning
6.Which of the following is an open loop control system ?
Field controlled D.C. motor
Ward leonard control
Metadyne
Stroboscope
ANSWER : : Field controlled D.C. motor
7.A control system in which the control action is somehow dependent on the output is known as
Closed loop system
Semiclosed loop system
Open system
None of the above
ANSWER : : Closed loop system
8.The output of a feedback control system must be a function of
reference and output
reference and input
input and feedback signal
output and feedback signal
ANSWER : : reference and output
9.A control system working under unknown random actions is called
computer control system
digital data system
stochastic control system
adaptive control system
ANSWER : : stochastic control system
10.Regenerative feedback implies feedback with
oscillations
step input
negative sign
positive sign
ANSWER : : positive sign
11.By which of the following the control action is determined when a man walks along a path ?
Brain
Hands
Legs
Eyes
ANSWER : : Eyes
12.A closed loop system is distinguished from open loop system by which of the following ?
Servomechanism
Feedback
Output pattern
Input pattern
ANSWER : : Feedback
13.In closed loop control system, with positive value of feedback gain the overall gain of the system will
decrease
increase
be unaffected
any of the above
ANSWER : : decrease
14.Which of the following should be done to make an unstable system stable ?
The gain of the system should be decreased
The gain of the system should be increased
The number of poles to the loop transfer function should be increased
The number of zeros to the loop transfer function should be increased
ANSWER : : The gain of the system should be increased
15.An automatic toaster is a ______ loop control system.
open
closed
partially closed
any of the above
ANSWER : : open
16.Which of the following devices are commonly used as error detectors in instruments ?
Vernistats
Microsyns
Resolvers
Any of the above
ANSWER : : Any of the above
17.Any externally introduced signal affecting the controlled output is called a
feedback
stimulus
signal
gain control
ANSWER : : stimulus
18.As a result of introduction of negative feedback which of the following will not decrease ?
Band width
Overall gain
Distortion
Instability
ANSWER : : Band width
19.A.C. servomotor resembles
two phase induction motor
Three phase induction motor
direct current series motor
universal motor
ANSWER : : two phase induction motor
20.A car is rtyining at a constant speed of 50 km/h, which of the following is the feedback element for the driver ?
Clutch
Eyes
Needle of the speedometer
Steering wheel
ANSWER : : Needle of the speedometer
21.In electrical-pneumatic system analogy the current is considered analogous to
velocity
pressure
air flow
air flow rate
ANSWER : : air flow rate
22.Mass, in force-voltage analogy, is analogous to
charge
current
inductance
resistance
ANSWER : : inductance
23.A control system with excessive noise, is likely to suffer from
saturation in amplifying stages
loss of gain
vibrations
oscillations
ANSWER : : saturation in amplifying stages
24.Which of the following statements is correct for any closed loop system ?
All the co-efficients can have zero value
All the co-efficients are always non-zero
Only one of the static error co-efficients has a finite non-zero value
None of the above
ANSWER : : Only one of the static error co-efficients has a finite non-zero value
25.Due to which of the following reasons excessive bond width in control systems should be avoided ?
It leads to slow speed of response
It leads to low relative stability
Noise is proportional to band width
None of the above
ANSWER : : Noise is proportional to band width
26.Which of the following statements is correct for a system with gain margin close to unity or a phase margin close to zero ?
The system is relatively stable
The system is highly stable
The system is highly oscillatory
None of the above
ANSWER : : The system is highly oscillatory
27.The transient response of a system is mainly due to
inertia forces
internal forces
stored energy
friction
ANSWER : : stored energy
28.The temperature, under thermal and electrical system analogy, is considered analogous to
voltage
current
capacitance
charge
ANSWER : : voltage
29.The band width, in a feedback amplifier.
remains unaffected
decreases by the same amount as the gain increase
increases by the sane saaaajajt as the gain decrease
decreases by the same amount as the gain decrease
ANSWER : : increases by the sane saaaajajt as the gain decrease
30.Zero initial condition for a system means
input reference signal is zero
zero stored energy
ne initial movement of moving parts
system is at rest and no energy is stored in any of its components
ANSWER : : system is at rest and no energy is stored in any of its components
31.In force-voltage analogy, velocity is analogous to
current
charge
inductance
capacitance
ANSWER : : current
32.On which of the following factors does the sensitivity of a closed loop system to gain changes and load disturbances depend ?
Frequency
Loop gain
Forward gain
All of the above
ANSWER : : All of the above
33.In liquid level and electrical system analogy, voltage is considered analogous to
head
liquid flow
liquid flow rate
none of the above
ANSWER : : head
34.Transfer function of a system is used to calculate which of the following ?
The order of the system
The time constant
The output for any given input
The steady state gain
ANSWER : : The output for any given input
35.The transient response, with feedback system,
rises slowly
rises quickly
decays slowly
decays quickly
ANSWER : : decays quickly
36.In force-voltage analogy, velocity is analogous to
charge
inductance
capacitance
ANSWER : : current
37.On which of the following factors does the sensitivity of a closed loop system to gain changes and load disturbances depend ?
Frequency
Loop gain
Forward gain
All of the above
ANSWER : : All of the above
38.In liquid level and electrical system analogy, voltage is considered analogous to
head
liquid flow
liquid flow rate
none of the above
ANSWER : : head
39.Transfer function of a system is used to calculate which of the following ?
The order of the system
The time constant
The output for any given input
The steady state gain
ANSWER : : The output for any given input
40.The transient response, with feedback system,
rises slowly
rises quickly
decays slowly
decays quickly
ANSWER : : decays quickly
41.A controller, essentially, is a
sensor
clipper
comparator
amplifier
ANSWER : : comparator
42.In an automatic control system which of the following elements is not used ?
Error detector
Final control element
Sensor
Oscillator
ANSWER : : Oscillator
43.The capacitance, in force-current analogy, is analogous to
momentum
velocity
displacement
mass
ANSWER : : mass
44.In thermal-electrical analogy charge is considered analogous to
heat flow
reciprocal of heat flow
reciprocal of temperature
temperature
ANSWER : : temperature
45.The second derivative input signals modify which of the following ?
The time constant of the system
Damping of the system
The gain of the system
The time constant and suppress the oscillations
ANSWER : : The time constant and suppress the oscillations
46.The viscous friction co-efficient, in force-voltage analogy, is analogous to
charge
resistance
reciprocal of inductance
reciprocal of conductance
ANSWER : : resistance
47.In a stable control system backlash can cause which of the following ?
Underdamping
Overdamping
Poor stability at reduced values of open loop gain
Low-level oscillations
ANSWER : : Low-level oscillations
48.In a control system the output of the controller is given to
final control element
amplifier
comparator
sensor
ANSWER : : final control element
49.Phase margin of a system is used to specify which of the following ?
Frequency response
Absolute stability
Relative stability
Time response
ANSWER : : Relative stability
50.The type 2 system has at the origin.
no net pole
net pole
simple pole
two poles
ANSWER : : two poles
51.Which of the following is the best method for determining the stability and transient response ?
Root locus
Bode plot
Nyquist plot
None of the above
ANSWER : : Root locus
52.An increase in gain, in most systems, leads to
smaller damping ratio
larger damping ratio
constant damping ratio
none of the above
ANSWER : : smaller damping ratio
53.The transfer function is applicable to which of the following ?
Linear and time-in variant systems
Linear and time-variant systems
Linear systems
Non-linear systems
ANSWER : : Linear and time-in variant systems
54.The position and velocity errors of a type-2 system are
constant, constant
constant, infinity
zero, constant
zero, zero
ANSWER : : zero, constant
55.In case of type-1 system steady state acceleration is
unity
infinity
zero
10
ANSWER : : infinity
56.By which of the following the system response can be tested better ?
Ramp input signal
Sinusoidal input signal
Unit impulse input signal
Exponentially decaying signal
ANSWER : : Unit impulse input signal
57.Spring constant in force-voltage analogy is analogous to
capacitance
reciprocal of capacitance
current
resistance
ANSWER : : reciprocal of capacitance
58.A conditionally stable system exhibits poor stability at
low frequencies
reduced values of open loop gain
increased values of open loop gain
none of the above
ANSWER : : reduced values of open loop gain
59.In a system zero initial condition means that
The system is at rest and no energy is stored in any of its components
The system is working with zero stored energy
The system is working with zero reference signal
The system is at rest and no energy is stored in any of its components
ANSWER : In a system low friction co-efficient facilitates
60.The type 0 system has ______ at the origin.
no pole
net pole
simple pole
two poles
ANSWER : : no pole
61.From which of the following transfer function can be obtained ?
Signal flow graph
Analogous table
Output-input ratio
Standard block system
ANSWER : : Signal flow graph
62.With feedback _____ increases.
system stability
sensitivity
gain
effects of disturbing signals
ANSWER : : system stability
63.The type 1 system has ______ at the origin.
no pole
net pole
simple pole
two poles
ANSWER : : simple pole
64.technique is not applicable to nonlinear system ?
Nyquist Criterion
Quasi linearization
Functional analysis
Phase-plane representation
ANSWER : : Nyquist Criterion
65.The frequency and time domain are related through which of the following?
Laplace Transform and Fourier Integral
Laplace Transform
Fourier Integral
Either (b) or (c)
ANSWER : : Laplace Transform and Fourier Integral
66.Velocity error constant of a system is measured when the input to the system is unit _______ function.
parabolic
ramp
impulse
step
ANSWER : : ramp
67.Addition of zeros in transfer function causes which of the following ?
Lead-compensation
Lag-compensation
Lead-lag compensation
None of the above
ANSWER : : Lag-compensation
68.In order to increase the damping of a badly underdamped system which of following compensators may be used ?
Phase-lead
Phase-lag
Both (a) and (b)
Either (a) and (b)
ANSWER : : Phase-lead
69.If a step function is applied to the input of a system and the output remains below a certain level for all the time, the system is
not necessarily stable
stable
unstable
always unstable
ANSWER : : not necessarily stable
70.Static error co-efficients are used as a measure of the effectiveness of closed loop systems for specified ________ input signal.
acceleration
velocity
position
all of the above
ANSWER : : all of the above
71.Which of the following is an electromechanical device ?
Induction relay
Thermocouple
LVDT
Any of the above
ANSWER : : LVDT
72.If the gain of the critical damped system is increased it will behave as
oscillatory
critically damped
overdamped
underdamped
ANSWER : : underdamped
73.A phase lag lead network introduces in the output
lag at all frequencies
lag at high frequencies and lead at low frequencies
lag at low frequencies and lead at high frequencies
none of the above
ANSWER : : lag at low frequencies and lead at high frequencies
74.Which of the following devices is used for conversion of co-ordinates ?
Microsyn
Selsyn
Synchro-resolver
Synchro-transformer
ANSWER : : Synchro-resolver
75.Pressure error can be measured by which of the following ?
Differential bellows and straingauge
Selsyn
Strain gauge
Strain gauge and potentiometer
ANSWER : : Differential bellows and straingauge
76.In a control system integral error compensation _______ steady state error
increases
minimizes
does not have any effect on
any of the above
ANSWER : : minimizes
77.Which of the following is the definition of proportional band of a controller ?
The range of air output as measured variable varies from maximum to minimum
The range of measured variables from set value
The range of measured variables through which the air output chan�ges from maximum to minimum
Any of the above
ANSWER : : The range of measured variables through which the air output chan�ges from maximum to minimum
78.The transfer function technique is considered as inadequate under which of the following conditions ? (a) Systems having complexities and non-linearities
Systems having stability problems
Systems having multiple input dis�turbances
All of the above
All of the above
ANSWER : Which of the following is the output of a thermocouple ?
79.A.C. servomotor is basically a
universal motor
single phase induction motor
two phase induction motor
three phase induction motor
ANSWER : : two phase induction motor
80.In pneumatic control systems the control valve used as final control element converts
pressure signal to electric signal
pressure signal to position change
electric signal to pressure signal
position change to pressure signal
ANSWER : : pressure signal to position change
81.A differentiator is usually not a part of a control system because it
reduces damping
reduces the gain margin
increases input noise
increases error
ANSWER : : increases input noise
82.Which of the following can be measured byLVDT?
Displacement
Velocity
Acceleration
Any of the above
ANSWER : : Any of the above
83.Which of the following can be measured by the use of a tacho-generator ?
Acceleration
Speed
Speed and acceleration
Displacement
ANSWER : : Speed
84.In a stable control system saturation can cause which of the following ?
Low-level oscillations
High-level oscillations
Conditional stability
Overdamping
ANSWER : : Low-level oscillations
85.The effect of error damping is to
provide larger settling lime
delay the response
reduce steady state error
any of the above
ANSWER : : reduce steady state error
86.With feed back _____ reduces.
system stability
system gain
system stability and gain
none of the above
ANSWER : : system gain
87.Which of the following is the non-linearity caused by servomotor ?
Static friction
Backlash
Saturation
None of the above
ANSWER : : Saturation
88.When the initial conditions of a system are specified to be zero it implies that the system is
at rest without any energy stored in it
working normally with reference input
working normally with zero reference input
at rest but stores energy
ANSWER : : at rest but stores energy
89.An amplidyne can give which of the following characteristics ?
Constant current
Constant voltage
Constant current as well as constant voltage
Constant current, constant voltage and constant power
ANSWER : : Constant current, constant voltage and constant power