Q1. A closed-loop control system uses:
(A)
No feedback
(B)
Feedback
(C)
Only manual control
(D) Fixed timing
Q2. An open-loop system
is one without:
(A)
Input
(B)
Feedback
(C)
Output
(D) Power
Q3. The transfer function is the ratio of Laplace of output to input with:
(A)
Max input
(B)
Zero initial conditions
(C)
Feedback removed
(D) Load removed
Q4. Transfer functions
are defined only for systems:
(A)
Non-linear
(B)
Linear time-invariant
(C)
Time-varying
(D) Discrete only
Q5. The closed-loop transfer
function of a unity-feedback system
is:
(A)
G
(B)
G/(1+G)
(C) 1+G
(D)
G·H
Q6. For a system
with forward path G and feedback H, C/R equals:
(A)
G·H
(B)
G/(1+GH)
(C) G+H
(D)
1/(GH)
Q7. The characteristic equation
of a feedback system is:
(A)
G=0
(B)
1+GH=0
(C) H=0
(D)
GH=1 only
Q8. The roots of the denominator of a transfer
function are the:
(A)
Zeros
(B)
Poles
(C) Gains
(D) Residues
Q9. A system is stable if all poles lie in the:
(A)
Right half of s plane
(B)
Left half s-plane
(C)
Imaginary axis
(D)
Origin
Q10. Mason's gain formula
is used with:
(A)
Block diagrams
(B)
Signal-flow graphs
(C) Bode plots
(D)
Root locus
Q11. Feedback in a control
system generally sensitivity to disturbances:
(A)
Increases
(B)
Reduces
(C) Does not change
(D)
Doubles
Q12. Negative feedback the overall gain but improves stability:
(A)
Increases
(B)
Reduces
(C) Removes
(D) Doubles
Q13. Which is NOT true?
(i) State model is unique
(ii) State space applies to MIMO/non-linear
(iii) TF is for LTI only
(iv) state model includes initial conditions.
NOT true is:
(A)
(ii)
(B) (iii)
(C)
(i) State model is unique
(D) (iv)
Q14. The state model of a given system
is:
(A)
Unique
(B)
Not unique
(C)
Always diagonal
(D) Zero
Q15. A transfer
function is applicable only for systems:
(A)
Non-linear
(B)
Linear time-invariant
(C)
Time-varying
(D) MIMO
Q16. A first-order system response has:
(A)
Overshoot
(B)
No overshoot
(C)
Oscillations
(D) Instability
Q17. The damping ratio for an undamped system is:
(A)
0
(B) 0.5
(C) 1
(D)
Infinite
Q18. A critically damped
system has damping
ratio:
(B)
0.5
(C)
1
(D)
0
(E)
2
Q19. An under-damped second-order system has damping
ratio:
(A)
Zero
(B)
Between 0 and 1
(C) Exactly 1
(D)
Greater than 1
Q20. The peak overshoot depends on the:
(A)
Natural frequency only
(B)
Damping ratio
(C) Gain only
(D)
Type number
Q21. The settling time (2%) of a second-order system is approximately:
(A)
4/(zeta·wn)
(B)
1/wn
(C) zeta·wn
(D) wn²
Q22. The damped natural frequency wd equals:
(A)
wn
(B) wn·sqrt(1-zeta²)
(C)
wn·zeta
(D) wn/zeta
Q23. Peak overshoot Mp is exp of:
(A)
-zeta·pi/sqrt(1-zeta²)
(B) -wn·t
(C)
-zeta·wn
(D) -pi
Q24. As damping ratio increases from 0 to 1, the overshoot:
(A)
Increases
(B)
Decreases
(C)
Stays same
(D) Becomes infinite
Q25. A type-1 system has steady-state error to a step input:
(A)
Finite
(B)
Zero
(C)
Infinite
(D) Negative
Q26. A type-0
system has steady-state error to a ramp input:
(A)
Zero
(B) Finite
(C)
Infinite
(D) Negative
Q27. The steady-state error for a first-order system G=1/(Ts+1) to a unit ramp is:
(A) 0
(B)
T
(C)
2T
(D)
Infinite
Q28. The velocity
error constant Kv is used for a input:
(A)
Step
(B)
Ramp
(C)
Parabola
(D) Impulse
Q29. System type is defined by the number
of poles at the:
(A)
Infinity
(B)
Origin
(C)
Right half
(D) Zeros
Q30. Increasing
the system type the steady-state error:
(A)
Increases
(B)
Reduces
(C)
Does not change
(D) Doubles
Q31. A system
is stable if its output
remains for a bounded input:
(A)
Zero
(B)
Bounded
(C) Infinite
(D)
Oscillatory
Q32. The Routh-Hurwitz criterion
determines stability from the:
(A)
Bode plot
(B)
Characteristic equation coefficients
(C) Step response
(D)
Nyquist plot
Q33. A system is stable by Routh if the first column has:
(A)
Alternating signs
(B)
All same sign
(C) One zero
(D)
Two zeros
Q34. The number of sign changes
in the Routh first column equals the number of:
(A)
Stable poles
(B)
Right-half-plane roots
(C) Zeros
(D)
Integrators
Q35. For G=30/[s(s+1)(s+T)], the closed loop is stable
for:
(A)
T>0
(B)
0<T<3
(C) T>5
(D)
3<T<5
Q36. A control system
is NOT stable if the damping ratio is:
(A)
Greater than 1
(B)
Equal to 1
(C)
Less than zero
(D) 0.5
Q37. A system is marginally stable
if poles lie on the:
(A)
Left half
(B)
Imaginary axis
(C) Right half
(D)
Origin only
Q38. A row of zeros in the Routh array indicates:
(A)
Stable system
(B)
Symmetrically located roots
(C) No roots
(D)
All
LHP roots
Q39. If all poles are in the LHS of the s-plane, the system is:
(A)
Unstable
(B)
Stable
(C) Marginally stable
(D)
Oscillatory
Q40. Absolute stability tells us whether a system is:
(A)
Fast
(B)
Stable or not
(C)
Accurate
(D) Damped
Q41. Relative stability is measured by:
(A)
Poles only
(B)
Gain and phase margins
(C)
Zeros
(D) Type number
Q42. The Hurwitz criterion
uses determinants of the:
(A)
Gain matrix
(B)
Coefficient (Hurwitz) matrix
(C)
State matrix
(D) Output matrix
Q43. For stability, all coefficients of the characteristic equation must be:
(A)
Zero
(B)
Present and of the same sign
(C)
Negative
(D) Complex
Q44. The Routh
array is built
from of the characteristic polynomial:
(A)
Roots
(B)
Coefficients
(C)
Poles
(D) Zeros
Q45. A necessary (not sufficient) condition
for stability is that all coefficients are:
(A)
Zero
(B)
Negative
(C)
Imaginary
(D)
Positive (same sign)
Q46. The root locus is the path of as gain K varies:
(A)
Zeros
(B)
Closed-loop poles
(C)
Open-loop zeros
(D) Inputs
Q47. The root locus
starts (K=0) at the open-loop:
(A)
Zeros
(B)
Poles
(C)
Origin
(D) Infinity
Q48. The root locus ends (K=infinity) at the open-loop:
(A)
Poles
(B)
Zeros (or infinity)
(C)
Origin
(D) Imaginary axis
Q49. The number of root-locus branches
equals the number of:
(A)
Zeros
(B)
Open-loop poles
(C) Loops
(D)
Inputs
Q50. The angle
of departure is calculated at a pole:
(A)
Real
(B)
Complex
(C) Zero
(D)
Origin
Q51. For G(s)=K/[s(s+4)(s²+4s+20)], the angle of departure at pole (-2+j4)
is:
(A)
-90 deg
(B) +90 deg
(C)
-74.7 deg
(D) +74.7 deg
Q52. A Bode plot shows
magnitude in versus
log frequency:
(A)
Volts
(B)
Decibels
(C) Amperes
(D)
Radians
Q53. A single
pole contributes a slope of to the Bode magnitude:
(A) +20 dB/dec
(B)
-20 dB/dec
(C) -40 dB/dec
(D) 0
Q54. A single
zero contributes a slope of to the Bode magnitude:
(A) -20 dB/dec
(B) +20 dB/dec
(C) -40 dB/dec
(D) 0
Q55 The gain Cross Over
Frequency is where the magnitude is
(A)
Maximum
(B)
0 dB (unity gain)
(C)
Minimum
(D) Infinite
Q56. For G=K/[s(s+1)], the K for gain crossover
frequency 10 rad/s is about:
(A)
1
(B) 10
(C)
1000
(D) 100
Q57. The phase crossover
frequency is where the phase is:
(A)
0 deg
(B)
-180 deg
(C) +90
deg
(D) -90
deg
Q58. The
gain margin is measured at the crossover
frequency:
(A)
Gain
(B)
Phase
(C) Zero
(D)
Break
Q59. The
phase margin is measured at the crossover
frequency:
(A)
Phase
(B)
Gain
(C) Break
(D)
Corner
Q60. A system with positive gain and phase margins is:
(A)
Unstable
(B)
Stable
(C) Marginal
(D)
Oscillatory
Q61. The Nyquist criterion
counts encirclements of the point:
(A)
(0,0)
(B)
(-1+j0)
(C) (+1+j0)
(D)
(0,-1)
Q62. In the Nyquist
relation N = Z - P, Z is the number of:
(A)
Open-loop RHP poles
(B)
Closed-loop RHP poles
(C) Zeros
(D)
Encirclements
Q63. A system is stable by Nyquist if Z equals:
(A)
1
(B)
Zero
(C) P
(D) N
Q64. For G=(s+2)/[(s+1)(s-1)], the number of encirclements of (-1+j0) is:
(A) 1 clockwise
(B)
2 clockwise
(C)
1 counterclockwise
(D)
zero
Q65. The Nyquist criterion is useful because it works even for systems with:
(A)
No poles
(B)
RHP open-loop poles
(C) Only zeros
(D)
No feedback
Q66. A larger phase margin means the system is:
(A)
Less stable
(B)
More relatively stable (better damped)
(C) Faster only
(D)
Unstable
Q67. The polar plot is the locus of G(jw) as w varies from:
(A)
0 to 1
(B)
0 to infinity
(C) -1 to 1
(D) 1 to 10
Q68. The M-circles and N-circles are used with the:
(A)
Root locus
(B)
Nyquist/polar plot
(C)
Bode plot
(D) Routh array
Q69. A minimum-phase system has all poles and zeros in the:
(A)
Right half
(B)
Left half
(C)
Origin
(D) Imaginary axis
Q70. The corner (break)
frequency of a first-order factor is at:
(A)
w=0
(B) w=1/T
(C)
w=T
(D) w=infinity
Q71. A lead compensator adds to the system:
(A)
Phase lag
(B)
Phase lead
(C)
Gain only
(D) Delay
Q72. A lead compensator improves
the response:
(A)
Steady-state
(B)
Transient (speed, overshoot)
(C)
DC
(D) Zero
Q73. A lag compensator improves
the accuracy:
(A) Transient
(B) Phase
(C) Bandwidth
(D) Steady -state
Q74. Phase-lead compensation is used to increase rise time speed and decrease:
(A)
Gain
(B)
Overshoot
(C)
Bandwidth
(D) Accuracy
Q75. Which is correct? (I) Phase lead increases rise time and
decreases overshoot (II) Phase lag improves relative stability. Correct answer:
(A)
Both correct
(B)
Only (II)
correct
(C)
Both wrong
(D) Only (I) correct
Q76. A lag-lead compensator combines the benefits
of:
(A)
Two lead
(B)
Lead and lag
(C)
Two lag
(D) PID only
Q77. In a PID controller, the integral term removes:
(A)
Overshoot
(B)
Steady-state error
(C) Rise time
(D)
Bandwidth
Q78. In a PID controller, the derivative term improves:
(A)
Steady-state error
(B)
Damping (transient)
(C) DC gain
(D)
Type number
Q79. The proportional term of a PID controller reduces the:
(A)
Damping
(B)
Error
(C) Bandwidth
(D)
Phase
Q80. The state equation
of a system is:
(A)
y=Cx+Du
(B)
x'=Ax+Bu
(C) x=Ay
(D)
u=Bx
Q81. The output equation
of a state model
is:
(A)
x'=Ax+Bu
(B)
y=Cx+Du
(C) x=Ay
(D) A=BC
Q82. The eigenvalues of the system
matrix A are the system:
(A) Zeros
(C) Gains
(D) Inputs
(E) Poles
Q83. A system is controllable if the controllability matrix has:
(A)
Zero rank
(B)
Full rank
(C)
One row
(D) No inverse
Q84. A system is observable if the observability matrix has:
(A)
Zero rank
(B)
Full rank
(C)
No columns
(D) Determinant zero
Q85. State-space methods
handle systems that transfer functions
cannot:
(A)
SISO linear
(B)
MIMO/non-linear/time-varying
(C)
DC
(D) Static
Q86. The state transition
matrix is given by:
(A)
e^(At)
(B)
At
(C) 1/A
(D)
A²
Q87. Which is NOT true about
control systems? State
model is:
(A)
Applicable to MIMO
(B)
Unique for a system
(C) Inclusive of initial
conditions
(D)
For non-linear systems
Q88. A phase-lag
network is basically
a filter:
(A)
High-pass
(B)
Low-pass
(C) Band-pass
(D)
Band-stop
Q89. A phase-lead network behaves like a filter:
(A)
Low-pass
(B)
High-pass
(C) Band-stop
(D)
All-pass
Q90. The compensator that increases bandwidth
is the:
(A)
Lag
(B)
Lead
(C) Notch
(D)
Integral
Q91. The Laplace transform of a unit step is:
(A)
1
(B)
1/s
(C)
1/s²
(D) s
Q92. The Laplace transform
of a unit impulse is:
(A)
0
(B)
1
(C) 1/s
(D)
s
Q93. The Laplace transform
of a unit ramp is:
(A)
1/s
(B)
1/s²
(C) s
(D)
1
Q94. The Laplace transform
of f(t)=2·sqrt(t/pi) is s^(-3/2). The Laplace of g(t)=sqrt(1/(pi·t)) is:
(A)
3s^(-5/2)
(B)
3s^(-5/2)/2
(C) s^(-1/2)
(D)
3s^(3/2)
Q95. The final-value theorem
gives f(infinity) = lim of:
(A)
s·F(s) as s->0
(B) F(s) as s->infinity
(C)
s·F(s) as s->infinity
(D) F(0)
Q96. The initial-value theorem
gives f(0) = lim of:
(A)
s·F(s) as s->0
(B) s·F(s) as s->infinity
(C)
F(s) as s->0
(D) F(infinity)
Q97. The inverse z-transform of 5/(1-0.2z^-1) is:
(A)
5(0.2)^k, k>=0
(B) (0.2)^k
(C)
5(0.2)^(k+1)
(D) 5(0.2)^(k-1)
Q98. The
z-transform is used for systems:
(A)
Continuous
(B)
Discrete-time
(C)
Analog
(D) Static
Q99. The region of convergence determines the of a z-transform:
(A)
Gain
(B)
Stability/causality
(C)
Frequency
(D) Phase
Q100. A discrete
system is stable
if all poles lie the unit circle:
(A)
Outside
(B)
Inside
(C)
Far From
(D)
on
Q101. Which Fourier-series statements are correct? For a
non-sinusoidal periodic waveform: (ii) odd rotational symmetry gives odd sine
terms; (iii) half-wave + even symmetry gives odd cosine terms.
Correct:
(A)
(i) and (ii)
(B) (iii) and (iv)
(C)
(i)
and (iv)
(D) (ii)
and (iii)
Q102. The Fourier series
of an even function contains:
(A)
Only sine terms
(B)
Constant and cosine
terms
(C)
Only odd harmonics
(D) No DC
Q103. The Fourier transform
converts a signal from time domain to:
(A)
Laplace domain
(B)
Frequency domain
(C)
z-domain
(D) State space
Q104. A periodic
signal has a frequency spectrum:
(A)
Continuous
(B)
Discrete (line)
(C) Zero
(D)
Infinite
Q105. The bilateral Laplace
transform is used for:
(A)
Causal signals only
(B)
Two-sided signals
(C) DC only
(D)
Periodic only
Q106. Resistance heating
uses the effect of current:
(A)
Magnetic
(B)
Heating (I²R)
(C) Capacitive
(D)
Corona
Q107. Induction heating heats the charge by inducing:
(A)
Voltage
(B)
Eddy currents
(C) Corona
(D)
Arc
Q108. Dielectric heating
is used for materials:
(A)
Conducting
(B)
Insulating (non-conducting)
(C) Magnetic
(D)
Metallic
Q109. An arc furnace
is used for:
(A)
Cooking
(B)
Lighting
(C)
Steel making
(D) Charging
Q110. The heating element
material Nichrome is an alloy of:
(A)
Copper and tin
(B)
Nickel and chromium
(C) Iron and carbon
(D)
Aluminium and silicon
Q111. Induction heating frequency
for surface hardening
is:
(A)
Very low
(B)
High (kHz range)
(C) Zero
(D)
DC
Q112. The main advantage
of induction heating is that heat is generated:
(A)
Outside the charge
(B)
Inside the charge itself
(C) In the coil
(D)
In
air
Q113. Resistance welding generates
heat by passing heavy current through the:
(A)
Electrode
(B)
Joint resistance
(C)
Air gap
(D) Transformer
Q114. Spot welding is a type of:
(A)
Arc welding
(B)
Resistance welding
(C)
Gas
welding
(D) Thermit welding
Q115. Arc welding uses a open-circuit voltage to strike the arc:
(A)
Low
(B)
High
(C)
Zero
(D) Negative
Q116. In DC arc welding with straight polarity, the work is the:
(A)
Cathode
(B)
Anode (positive)
(C)
Neutral
(D) Ground only
Q117. The temperature of an electric
arc is about:
(A)
100 C
(B) 500 C
(C)
Several thousand degrees C
(D) 50 C
Q118. Thermit welding uses
the heat of a chemical reaction of:
(A)
Copper
(B)
Zinc
(C)
Aluminium and iron oxide
(D) Nickel
Q119. Seam welding
produces a weld:
(A)
Single spot
(B)
Continuous
(C)
Butt
(D) Arc
Q120. The power factor of
a resistance-welding transformer is usually:
(A)
Unity
(B)
Low (highly inductive)
(C)
Leading
(D) Zero
Q121. Luminous flux is measured in:
(A)
Candela
(B)
Lumen
(C)
Lux
(D) Watt
Q122. Luminous intensity is
measured in:
(A)
Lumen
(B)
Candela
(C) Lux
(D)
Watt
Q123. Illumination (illuminance) is measured in:
(A)
Candela
(B)
Lumen
(C)
Lux
(D)
Watt
Q124. One lux equals one lumen per:
(A)
Metre
(B)
Square metre
(C) Candela
(D)
Watt
Q125. Illumination follows
the inverse- law with distance:
(A)
Linear
(B)
Square
(C) Cube
(D)
Log
Q126. The luminous efficacy
of a lamp is measured
in:
(A)
Lumen
(B)
Lumens per watt
(C) Lux
(D) Candela
Q127. The lamp with the highest
efficacy is the:
(A)
Incandescent
(B)
LED
(C)
Filament
(D)
Carbon arc
Q128 The Cosine law of
Illumination accounts for the ____of the surface
(A)
Colour
(B)
Angle of incidence
(C)
Distance only
(D) Area only
Q129. A sodium-vapour lamp gives light
of colour:
(A)
Blue
(B)
Yellow (monochromatic)
(C)
White
(D) Red
Q130. The coefficient of utilisation in lighting design
accounts for:
(A)
Lamp watt
(B)
Light reaching the working plane
(C)
Voltage
(D) Frequency
Q131. Fluorescent lamps require a to limit current:
(A)
Resistor only
(B)
Ballast (choke)
(C) Capacitor only
(D)
Diode
Q132. The maintenance factor in lighting accounts for:
(A)
New lamps
(B)
Dirt and ageing depreciation
(C) Voltage rise
(D)
Colour
Q133. Electric traction
offers high at starting:
(A)
Voltage
(B)
Torque
(C) Resistance
(D)
Frequency
Q134. The speed-time
curve phases are: acceleration, free run, coasting and:
(A)
Reversing
(B)
Braking
(C) Charging
(D)
Idling
Q135. During coasting,
the traction motor is:
(A)
At full power
(B)
Switched off (power
removed)
(C) Braking
(D)
Reversed
Q136. Regenerative braking returns energy to the:
(A)
Motor
(B)
Supply
(C) Brakes
(D) Wheels
Q137. The DC series
motor was traditionally used in traction
for its high:
(A)
Starting torque
(B)
Efficiency
(C)
Speed
(D)
Power factor
Q138. The schedule
speed of a train is the average
speed:
(A)
Greater than
(B)
Less than (includes stops)
(C) Equal to
(D)
Twice
Q139. Modern electric
locomotives use motors with power-electronic drives:
(A)
DC shunt
(B)
Three-phase induction
(C) Single-phase
(D)
Universal
Q140. The specific energy consumption of a train is expressed
in:
(A)
kWh
(B)
Wh per tonne-km
(C) kW
(D) Volt
Q141. The tractive effort
is the force needed to:
(A)
Brake
(B)
Accelerate and overcome
resistance
(C)
Stop
(D) Reverse
Q142. Overhead traction supply in Indian railways is:
(A)
1500
V DC
(B)
25 kV AC, 50 Hz
(C)
3000 V DC
(D) 11 kV DC
Q143. The composite speed-time curve is used for:
(A)
Main-line service
(B)
Suburban/urban service
(C)
Freight only
(D) Coasting only
Q144. The adhesion between
wheel and rail limits the maximum:
(A)
Voltage
(B)
Tractive effort
(C)
Speed only
(D) Braking only
Q145. A quadrilateral speed-time
curve is an approximation for:
(A)
Main-line
(B)
Suburban service
(C)
Coasting
(D) Free run only
Q146. Rheostatic braking dissipates
the motor energy in:
(A) Supply
(B) Brakes
(C) Resistors (As heat)
(D) Wheels
Q147. The main advantage
of AC traction over DC is:
(A)
Lower voltage
(B)
Cheaper substations, lighter
overhead
(C)
More corona
(D) Higher current
Q148. A booster transformer in AC traction
reduces:
(A)
Voltage
(B)
Interference in communication lines
(C)
Speed
(D) Torque
Q149. Plugging is a braking
method that the motor supply:
(A)
Removes
(B)
Reverses
(C)
Doubles
(D) Shorts
Q150. The tractive effort required is highest during the phase:
(A)
Coasting
(B)
Acceleration
(C) Free run
