Exam Details
| Subject | electrical engineering | |
| Paper | paper 2 | |
| Exam / Course | ||
| Department | ||
| Organization | Uttarakhand Public Service Commission | |
| Position | assistant engineer | |
| Exam Date | 2013 | |
| City, State | uttarakhand, |
Question Paper
1. Which block replacement algorithm is not generally used in cache operation:
LIFO
FIFO
LRU
Random
2. The microprograms provided by a manufacturer to be used on his microprogrammed computer are generally called:
Software
Netware
Firmware
Hardware
3. The software that transfers the object program from secondary memory to the main memory is called:
Assembler
Loader
Linker
Task builder
4. A major advantage of active filters is that they can be realized without using:
Op-amps
Inductors
Resistors
Capacitors
5. The order of convergence of Newton-Raphson method
1
1.618
6. If is a polynomial of degree then . n is equal
0
Constant
None of these
7. Newton Raphson method is suitable in the cases where:
is large
is small
is negative
is positive
8. Value of
(unity being the interval of differencing)
-180
-90
-45
0
9. The relation between E and
2
10. The value of E2x2 when the value of x vary by a constant increment of
x2-8x+16
x2+8x+16
x2-8x+8
x2+8x+8
11. ACK indicates reception
Correct data
Incorrect data
Insufficient data
Sufficient data
12. 8085 Microprocessor does not have:
Zero flag
Parity flag
Over flag
Auxiliary carry flag
13. Which of the following is used for serial access storage only:
RAM
Magnetic tape
Magnetic disk
Core memory
14. The Runge Kutta method of second order is nothing but:
Euler method
Taylor method
Modified Euler method
Improved Euler method
15. Which byte of an instruction is loaded into IR register?
Last
First
Both of above
None of above
16. In an instruction of 8085 microprocessor, how many bytes are present?
One only
One or Two
Two or Three
One, Two or Three
17. Zero address instruction format is used for:
RISC architecture
CISC architecture
Von Neuman architecture
Stack- organised architecture
18. Which bus is a bidirectional bus:
Address bus
Data bus
Address bus and data bus
None of the above
19. Which one of the following is not a vectored interrupt?
INTR
TRAP
RST 3
RST 7.5
20. The total number of pins in 8085 are:
20
30
40
50
21. Which of the following instructions have only one operand?
Multiply
Add
Shift
Subtract
22. In a microprocessor, the address of the next instruction to be executed is stored
Stack pointer
Address latch
Program counter
General purpose register
23. In 8085 microprocessor, after the execution of XRA A instruction
The carry flag is set
The accumulator contain FFH
The zero flag is set
The accumulator contents are shifted left by one bit
24. In 8085 microprocessor the contents of the accumulator, after the following instruction executed will become:-X RA A MVIB FOH SUB B
01 H
0F H
F0 H
10 H
25. Decimal number is represented in compliment form
0 1 0 0
1 0 1 1
1 1 0 0
1 0 1 0
26. The instruction that exchanges stack top with HL pair
PUSH H
S P H L
X T H L
P C H L
27. In 8255, port C can work as 8 bit port
Mode 0 only
Mode 1 only
Mode 2 only
None of the above
28. The chip 8255 A is connected as peripheral I/O. The chip is selected when address lines A2 to A7 are all the address of control register
FC H
FD H
FE H
FF H
29. The ADC that has maximum clock periods equal to number of bits
Dual slope ADC
Counter ramp ADC
Successive approximation ADC
Flash converter ADC
30. The 8259 A programmable Interrupt controller in cascade mode can handle interrupts
8 priority level
16 priority level
32 priority level
64 priority level
31. Boolean expression y z xy z x z xyz can be simplified
xz z yz
xz z yz
y xyz xz
xyz z
32. The minimum number of NAND gates required to implement is equal
Zero
1
33. Decimal equivalent of the hexadecimal number E5
279
229
427
3000
34. What overall accuracy could one reasonably expect from construction of a 10 bit A/D converter?
0.1%
0.2%
0.3%
0.4%
35. At s the torque of an induction motor
Zero
Equal to full load torque
Very high
Very low
36. The least expensive protection for over current in low voltage system
Rewirable fuse
Isolator
Circuit breaker
Air Break switch
37. The Air Blast circuit breakers for 400 kV system are designed to operate
0.1 s
0.5 s
50 ms
100 µs
38. Which of the following circuits come under the class of sequential logic circuits:
Full adder
Full subtractor
Half adder
J-K flip counter
39. What are the output bit s and c (carry) of a Half adder having Input A=1 and
1
0
1
0
40. The motor normally used for crane travel
AC slip ring motor
Ward Leonard controlled DC shunt motor
Synchronous motor
DC differentially compounded motor
41. What are the number of Memories required of size 16x4 to design a Memory of size 64x8
42. The device commonly used for triggering a triac
Diode
Transistor
Zener diode
Diac
43. The r.m.s. value of a Half-wave Rectified symmetrical square wave current of 2A
route 2A
1 A
route 2A
route 3A
44. In d.c choppers, per unit ripple is Maximum, when duty cycle a
0.2
0.5
0.7
0.9
45. For separating the channels in FDM, one has to use:
Differentiator
Integrator
Band pass filter
AND gates
46. Modulation is Primarily accomplished
Produce side bands
Mix two-waves of different frequencies
Improve transmission efficiency
Transmit audio-frequency signal over long distance
47. In an AM wave, V max=10V and V min =5V The percentage of Modulation
20.00
33.33
50.00
75.00
48. A type of chopper has a source voltage load resistance and duty cycle . For this chopper, the rms value of the output voltage may
route alpha
alpha)· V
49. The software used to drive microprocessor based system is called:
Assembly language
Firm ware
High level language
Basic interpreter instructions
50. How may switches are used to construct a 3-to 3-cycloconverter?
12
18
51. How many bits are used in data bus of 8085?
52. A register in the microprocessor that keeps track of the answer or result of any arithmatic or logic operation is the:
Stack pointer
Program counter
Instruction pointer
Accumulator
53. Ready pin of a Microprocessor is used:
To indicate that the µ is ready to receive I/P
To indicate that the µ is ready to receive O/P
To introduce wait states
To provide direct memory access
54. In which T-state does the CPU sends the address to memory or I/O the ALE signal for demultiplexing:
T1
T2
T3
T4
55. is equivalent
ABC
A B C
A. B. C.
56. The figure of merit is minimum
I2L
NMOS
ECL
TTL
57. In a thyristor, holding current
More than latching current
Less than latching current
Equal to latching current
Cannot compare with latching current
58. The PIV of a half wave rectifier circuit with a shunt capacitor filter
(a) 2V m
V m
V 2
3Vm
59. The ripple factor of a Power supply is a measure
Its filter efficiency
Its voltage regulation
Diode rating
Purity of Power output
60. In a three phase half wave rectifier, each diode conducts for a duration
30°
60°
120°
180°
61. A step up chopper has V as the source voltage and a as the duty cycle. The output voltage s for this chopper is given
Vs
None of these
62. In single pulse modulation of PWM inverter, third harmonic can be eliminated if pulse width is equal
30°
60°
120°
None of these
63. In dc chopper, the waveforms for input and output voltage are respectively:
Discontinuous, Continuous
Both continuous
Both discontinuous
Continuous, discontinuous
64. If in a rectifier the ripple voltage is 150 mV and the dc value is 15V, then ripple factor is given
0.01
0.02
0.001
0.002
65. If two ends of rods are to be welded, the method of welding
Spot welding
Projection welding
Seam welding
Butt welding
66. A three phase diode bridge rectifier is fed from a 400V RMS, 50Hz, three phase AC source. If the load is purely resistive, then peak instantaneous voltage is equal
400 V
400 V
400 route2/3v
400/ route3 V
67. In a 3-ph bridge inverter with 180° conduction, the number of switches that are at any instant of time
68. A 1-ph full bridge inverter can have load commutation only if the load
R-L
underdamped
overdamped
critically damped
69. A 3-ph induction motor under dc dynamic braking work
Induction generator
dc generator
dc motor
synchronous generator
70. A chopper circuit is operating on TRC principle at a frequency of 2kHz on 230 V supply. If the load voltage is 184V, the on time and off time (Toff of chopper are respectively:
Ton=0.3 msec, Toff=0.2 msec
Ton =0.38 msec, Toff=0.12 msec
Ton =0.2 msec, Toff=0.3 msec
Ton =0.4 msec, Toff=0.1 msec
71. The number of terms in a logic function of three variables are:
72. Which of the following is an invalid state in Binary coded Decimal counter:
1 0 0 0
1 0 0 1
0 0 1 1
1 1 0 0
73. Which of the following is a sequential circuit?
AND gate
NAND gate
Bistable multivibrator
EX-OR gate
74. The output X of the OR gate show in figure
<img src='./qimages/3399-74.jpg'>
0
2
3
75. The Boolean expression A is equal
1
B
A
A+B
76. If the J-K Flip flop's output is zero, then in order to change its output to the input combination
J K X
J K X
J K=1
J K 0
77. How many 3-line to 8-line decoders are required for a 1 of 32 decoder?
78. The output Y of the logic circuit given below
X
79. When a BJT is used as a switch, its mode of operation switches between:
Cut-off and active regions
Cut-off and saturation regions
Active and saturation regions
Different operating points in the active region
80. The most suitable gate for comparing two bit
AND gate
OR gate
NAND gate
EX-OR gate
81. Which of the following finds application in pocket calculator?
TTL
CMOS
ECL
Both and
82. Which has the lowest propagation delay time?
ECL
TTL
CMOS
DMOS
83. De Morgan's second theorem
A .
A
.
84. The minimum number of NOR gates A required to implement is equal
85. In a 6 bit Johnson counter sequence, there are a total of how many states or bit patterns?
12
24
86. The most powerful solid state microwave device
GUNN diode
IMPATT diode
MESFET
Varactor
87. The following wave does not exist in wave guides:
TE waves
TM waves
TEM
TE TEM
88. The characteristic Impedance of a lossless transmission line is given
Z
Z routeC/L
Z routeL/C
Z LC
89. The characteristic impedance of a cable is about:
300 omegha
50
90. As frequency is increased, the skin effect:
Increases
Decreases
Remains the same
Either or
91. The most noise immune system
SSB
PCM
PDM
PWM
92. Human ears can detect sound intensity of order
10-4 W/m2
10-8 W/m2
10-13 W/m2
10-18 W/m2
93. An AM wave is given by 0.5 cos 103 t 0.3 cos 104t. cos 106t), the modulation index of the envelope
0.5
0.58
0.3
0.8
94. A phase locked loop is a feedback circuit consisting of
Phase detector
Low pass filter
VCO
All of the above
95. An antenna has a resistance of 50 and an equivalent noise resistance of 30 . The noise figure in decibels
1.6 dB
2 dB
3.6 dB
6 dB
96. A carrier is modulated by two modulating waves A and B having modulation index of 0.6 and 0.8 respectively. The overall modulation index
1.0
0.7
0.2
1.4
97. In transistor radio receiver, the number of IF amplifier stages are:
98. For an ideal 3000Hz channel, S/N ratio
3
1.5
99. A waveguide section in microwave circuit acts
Low pass filter
Band pass filter
High pass filter
Band stop filter
100. Which TM mode in rectangular waveguide has lowest cut-off frequency?
TM11
TM01
TM10
TM21
101. A line has Z0=300 O . If ZL= 150 O reflection coefficient
0.5
0.333
-0.333
-0.5
102. Which of the following lines is non-radiating?
Open two wire
Co-axial
Both of the above
None of the above
103. Which of the following devices uses a helix?
Klystron Amplifier
Klystron Oscillator
TWT
Both and
104. A 6-pole, 50Hz, 3-phase induction motor has rotor resistance of 0.25 ohm and develops the maximum torque at 875 rpm. The rotor reactance and slip at the maximum torque respectively are:
2 0.125 pu
2 0. 25 pu
1 0. 25 pu
1 0.125 pu
105. The field excitation of 20A results in a short circuit armature current of 400A and open circuit terminal voltage of 2000V in an alternator. The magnitude of the internal voltage drop within the machine at a load current of 200A is
1 V
10 V
100 V
1000 V
106. What is the ratio of starting torque and maximum torque of a 3-phase, 50Hz, 4-pole induction motor when the maximum torque occurs at 1200 rpm?
0.384
0.421
0.5
0.6
107. A balanced three phase induction motor runs at slip If is the synchronous speed, what is the relative speed between the stator mmf and the rotor mmf?
s s
s
s
Zero
108. The supply voltage to a 3-phase induction motor is reduced by 10 percent. By what percentage will the maximum torque decrease?
12.1%
19.0%
21.0%
40.0%
109. Wide speed control range of three phase squirrel cage induction motor is obtained
Variable voltage constant frequency control method
Slip power recovery method
Pole changing method
Constant voltage to frequency ratio method
110. A 6-pole, 3-phase alternator running at 1000 rpm supplies to an 8-pole, 3-phase induction motor which has a rotor current of frequency 2 Hz. The speed at which the motor operates
1000 rpm
960 rpm
750 rpm
720 rpm
111. A synchronous motor is operating on no load at unity power factor, if the field current is increased, the power factor will become:
Leading and the stator current will decrease
Lagging and the stator current will increase
Lagging and the stator current will decrease
Leading and the stator current will increase
112. A synchronous motor is operated from a bus voltage of 1.0 pu and is drawing 1.0 pu zero power factor leading current. Its synchronous reactance is 0.5 pu What is the excitation emf of the motor?
0.5
1.0
1.5
2.0
113. Damper in a large generator is used
Increase stability
Reduce Voltage fluctuation
Reduce frequency fluctuation
All above
114. A 10 pole AC generator rotates at 1200 rpm. The frequency of AC voltage in cycle per second will
120
110
100
50
115. Speed of a repulsion motor at No load
Low
Very low
High
Dangerously high
116. What is the ratio of No-load speed to full load speed of a 200 kVA, 12 pole, 220V, 3 phase, 60 Hz synchronous motor?
1
1.1
1.21
Infinite
117. The motor used in household refrigerators
dc series motor
dc shunt motor
universal motor
Single phase induction motor
118. An ideal transformer does not-change:
Voltage
Power
Current
None of the above
119. The slip of an induction motor normally does not depend
Rotor speed
Synchronous speed
Shaft torque
Core-loss component
120. Skewing is used in induction motors in order to reduce torque due
Time harmonics
Space harmonics
Slot harmonics
Reverse rotating fields
121. Which type of motor is most suitable for computer printer device?
Reluctance motor
Hysterisis motor
Shaded pole motor
Stepper motor
122. In a circle diagram of a three phase induction motor the point where tangent to the circle is parallel to the horizontal line represents:
Maximum torque
Maximum output power
Maximum input
Stator loss
123. In a split phase motor, the ratio of number of turns for starting winding to that for running winding
2.0
More than 1.0
1.0
Less than 1.0
124. A 3 3 stack, variable reluctance step motor has 20 poles on each rotor and stator stack. The step angle of this step motor
3°
6°
9°
18°
125. Which of the following is an unexcited single phase synchronous motor?
A.C. series motor
Reluctance motor
Universal motor
Repulsion motor
126. A 60 Hz induction motor runs at 1150 rpm, its synchronous speed
1300 rpm
1500 rpm
1200 rpm
1000 rpm
127. The common type of servo motor is different from normal induction motor as it has:
Lower rotor resistance
Higher rotor resistance
Higher power rating
Larger inertia
128. When a 3-phase alternator is suddenly short circuited at its terminals, the initial value of short circuit current is limited by which one of the following?
Subtransient reactance
Transient reactance xd
Synchronous reactance x s
Sum of xd xd and x s
129. The domestic mixer uses an electric motor of type:
Universal motor
Shaded pole motor
Synchronous motor
Induction motor
130. The rotor power output of three phase induction motor is 15kW. The rotor copper loss at a slip of will
600W
625W
650W
700W
131. The change in speed of a 3 f induction motor from No load to full load is about:
15%
50%
132. A three phase induction motor takes A ampere on full load at a power factor of cos f . The component responsible for producing magnetization is approximately:
A sin
A tan
A cos
A cos
133. Synchronous motor can run
Leading power factor
Lagging power factor
Unity power factor
Any of above
134. As the load on a synchronous motor is increased, the torque angle:
Increases
Decreases
Remains same
None of these
135. If a dc series motor is connected to AC supply, then:
It will not run
It will run
It will burn out
It will pulsate
136. Which type of connection is employed for current transformers for the protection of star- delta connected 3-phase transformer
Delta Delta
Star Star
Star Delta
Delta Star
137. The relay used for protection of high voltage a.c. transmission line against power swing
Instantaneous overcurrent relay
Impedance relay
Mho relay
Reactance relay
138. The restriking voltage in circuit breaker is measured
RMS value
Peak value
Instantaneous value
Average value
139. The most suitable circuit breaker for interrupting short line fault without resistance switching
Minimum oil circuit breaker
SF6 circuit breaker
Bulk oil circuit breaker
Air blast circuit breaker
140. Which one of the following is not a routine test of a circuit breaker?
Short circuit test
Dielectric test
Thermal test
DC resistance voltage drop test
141. What is the approximate value of the surge impedance loading of a 400kV, 3-phase, 50Hz overhead single circuit transmission line?
230 MW
400 MW
1000 MW
1600 MW
142. How many relays are used to detect interphase fault of a three phase system?
One
Two
Three
six
143. Circuit breaker is used for which of the following:
Voltage control
Power control
Frequency control
Over current protection
144. Which is preferred type of C.B to be installed in EHV system?
Vacuum C.B.
Air blast C.B.
Bulk oil C.B.
None of these
145. If the fault current is 2000 the relay setting is 50% and CT ratio is 400 the plug setting multiplier will
25 A
15 A
50 A
10 A
146. In an open ended line, the reflection coefficient of current
147. Resistance switching is normally employed
All breakers
Bulk oil breakers
Minimum oil breakers
Air blast breakers
148. In an Indoor substation for 220 kV, the circuit breakers will be of the type:
Oil
Air break
SF6
Vacuum
149. The term critical clearing time in protection of Power system is related
Reactive power limit
Steady state stability limit
Short circuit current limit
Transient stability limit
150. The rate of rise of restriking voltage depends
Resistance and inductance of the system only
Inductance of system only
Capacitance of the system only
Inductance and capacitance of the system only
151. A relay with inherent directional characteristic
Mho relay
Impedance relay
Reactance relay
Differential relay
152. Loss of excitation in an alternator can be detected by using:
Earth fault relay
IDMT relay
Reactance relay
Offset Mho relay
153. In a circuit breaker, the time duration form the instant of the fault to the extinction of arc is known
Total clearing time
Operation time
Protection time
Recovery time
154. The making current of a 3-phase circuit breaker with rating 2000 MVA, 33kV will
35 kA
50 kA
70 kA
89 kA
155. If the percentage reactance of the system upto the fault point is 20% and the base kVA is 10,000 then the short circuit VA
10 MVA
20 MVA
50 MVA
60 MVA
156. Impedance relay can be used for:
Earth fault only
Phase fault only
Both earth and phase fault
None of these
157. Merz Price Protection is used to protect:
Transmission line and transformers
Transformers and generators
Motors only
Transformers only
158. For a fault at terminals of the synchronous generator, the fault current is maximum for
3 Phase fault
3 to ground fault
Line to ground fault
Line to line fault
159. A three phase, 33kV oil circuit breaker is rated for 1200 2000 MVA, 3s. The symmetrical breaking current
1200A
3600 A
35 kA
104.8 kA
160. A thermal protection switch provides protection against:
Over load
Under voltage
Short circuit
Over voltage
161. Using Euler's method, the value of y after 1st iteration for the differential equation
with y=1 when x=0 and h=0.1
1.0
1.1
1.2
Cannot be obtained due to insufficient data
162. The circuit shown
<img src='./qimages/3399-162.jpg'>
Inverting amplifier
Non inverting amplifier
Voltage to current convertor
Voltage follower
163. A unit positive step is applied at the input of the circuit shown below. After 15 seconds, the output Vo will
<img src='./qimages/3399-163.jpg'>
164. For the following analog simulation, the dynamic equation
<img src='./qimages/3399-164.jpg'>
165. Which one of the following methods is used for numerical integration?
Newton Raphson method
Lagrange's method
Trapezoidal rule
None of above
166. For solving equation x3-3x+1 0 by Newton Raphson method, the initial guess be next estimate x1 will
0.212
0.333
0.40
0.425
167. An op-Amp has a slew rate of 5V/ µ s. The largest sine wave o/p voltage possible at a frequency of 1MHz
10 V
5 V
V
5 2 V
168. To fit y=abx in linear form
y=cx+a
y=ax+c
ay=cx
y=x where x=xb
169. Interpolation is a technique of estimating the value of a function for any:
Minimum value of a variable
Intermediate value of a variable
Maximum value of a variable
None of these
170. A differential amplifier has a differential gain of 20,000 and CMRR=80db. The common mode gain is given
2
1
1/2
2.5
171. An ideal differential amplifier has CMRR equaling:
Unity
Zero
172. Using Runge Kutta fourth order method, the approximate value of y when x 0.2, given
that x+y when x 0 is given
1.3428
1.2421
1.2428
1.4345
173. The general solution of the differential equation
dx/dy x/y x/tany
sin
sin
cos
cos
174. Which of the following formula is most accurate for numerical integration?
Simpson's rule
Trapezoidal rule
Weddle's formula
Gauss's Quadrature formula
175. The value of
<img src='./qimages/3399-175.jpg'>
176. The differential equation t2 0 is called:
Fourier's equation
Laplace equation
Bessel's equation of index n
Hamiltonian equation
177. Effective address is calculated by adding or subtracting displacement value
Intermediate address
Relative address
Absolute address
Base address
178. If two stages with noise figure F1 and F2 and gains G1 G2 are cascaded, the resultant noise F will
179. The input resistance Ri and output resistance Ro of an Ideal current amplifier in Ohms are:
0 and 0
0 and infinity
and 0
and
180. If the input to an antilog amplifier is the output is proportional
<img src='./qimages/3399-180.jpg'>
LIFO
FIFO
LRU
Random
2. The microprograms provided by a manufacturer to be used on his microprogrammed computer are generally called:
Software
Netware
Firmware
Hardware
3. The software that transfers the object program from secondary memory to the main memory is called:
Assembler
Loader
Linker
Task builder
4. A major advantage of active filters is that they can be realized without using:
Op-amps
Inductors
Resistors
Capacitors
5. The order of convergence of Newton-Raphson method
1
1.618
6. If is a polynomial of degree then . n is equal
0
Constant
None of these
7. Newton Raphson method is suitable in the cases where:
is large
is small
is negative
is positive
8. Value of
(unity being the interval of differencing)
-180
-90
-45
0
9. The relation between E and
2
10. The value of E2x2 when the value of x vary by a constant increment of
x2-8x+16
x2+8x+16
x2-8x+8
x2+8x+8
11. ACK indicates reception
Correct data
Incorrect data
Insufficient data
Sufficient data
12. 8085 Microprocessor does not have:
Zero flag
Parity flag
Over flag
Auxiliary carry flag
13. Which of the following is used for serial access storage only:
RAM
Magnetic tape
Magnetic disk
Core memory
14. The Runge Kutta method of second order is nothing but:
Euler method
Taylor method
Modified Euler method
Improved Euler method
15. Which byte of an instruction is loaded into IR register?
Last
First
Both of above
None of above
16. In an instruction of 8085 microprocessor, how many bytes are present?
One only
One or Two
Two or Three
One, Two or Three
17. Zero address instruction format is used for:
RISC architecture
CISC architecture
Von Neuman architecture
Stack- organised architecture
18. Which bus is a bidirectional bus:
Address bus
Data bus
Address bus and data bus
None of the above
19. Which one of the following is not a vectored interrupt?
INTR
TRAP
RST 3
RST 7.5
20. The total number of pins in 8085 are:
20
30
40
50
21. Which of the following instructions have only one operand?
Multiply
Add
Shift
Subtract
22. In a microprocessor, the address of the next instruction to be executed is stored
Stack pointer
Address latch
Program counter
General purpose register
23. In 8085 microprocessor, after the execution of XRA A instruction
The carry flag is set
The accumulator contain FFH
The zero flag is set
The accumulator contents are shifted left by one bit
24. In 8085 microprocessor the contents of the accumulator, after the following instruction executed will become:-X RA A MVIB FOH SUB B
01 H
0F H
F0 H
10 H
25. Decimal number is represented in compliment form
0 1 0 0
1 0 1 1
1 1 0 0
1 0 1 0
26. The instruction that exchanges stack top with HL pair
PUSH H
S P H L
X T H L
P C H L
27. In 8255, port C can work as 8 bit port
Mode 0 only
Mode 1 only
Mode 2 only
None of the above
28. The chip 8255 A is connected as peripheral I/O. The chip is selected when address lines A2 to A7 are all the address of control register
FC H
FD H
FE H
FF H
29. The ADC that has maximum clock periods equal to number of bits
Dual slope ADC
Counter ramp ADC
Successive approximation ADC
Flash converter ADC
30. The 8259 A programmable Interrupt controller in cascade mode can handle interrupts
8 priority level
16 priority level
32 priority level
64 priority level
31. Boolean expression y z xy z x z xyz can be simplified
xz z yz
xz z yz
y xyz xz
xyz z
32. The minimum number of NAND gates required to implement is equal
Zero
1
33. Decimal equivalent of the hexadecimal number E5
279
229
427
3000
34. What overall accuracy could one reasonably expect from construction of a 10 bit A/D converter?
0.1%
0.2%
0.3%
0.4%
35. At s the torque of an induction motor
Zero
Equal to full load torque
Very high
Very low
36. The least expensive protection for over current in low voltage system
Rewirable fuse
Isolator
Circuit breaker
Air Break switch
37. The Air Blast circuit breakers for 400 kV system are designed to operate
0.1 s
0.5 s
50 ms
100 µs
38. Which of the following circuits come under the class of sequential logic circuits:
Full adder
Full subtractor
Half adder
J-K flip counter
39. What are the output bit s and c (carry) of a Half adder having Input A=1 and
1
0
1
0
40. The motor normally used for crane travel
AC slip ring motor
Ward Leonard controlled DC shunt motor
Synchronous motor
DC differentially compounded motor
41. What are the number of Memories required of size 16x4 to design a Memory of size 64x8
42. The device commonly used for triggering a triac
Diode
Transistor
Zener diode
Diac
43. The r.m.s. value of a Half-wave Rectified symmetrical square wave current of 2A
route 2A
1 A
route 2A
route 3A
44. In d.c choppers, per unit ripple is Maximum, when duty cycle a
0.2
0.5
0.7
0.9
45. For separating the channels in FDM, one has to use:
Differentiator
Integrator
Band pass filter
AND gates
46. Modulation is Primarily accomplished
Produce side bands
Mix two-waves of different frequencies
Improve transmission efficiency
Transmit audio-frequency signal over long distance
47. In an AM wave, V max=10V and V min =5V The percentage of Modulation
20.00
33.33
50.00
75.00
48. A type of chopper has a source voltage load resistance and duty cycle . For this chopper, the rms value of the output voltage may
route alpha
alpha)· V
49. The software used to drive microprocessor based system is called:
Assembly language
Firm ware
High level language
Basic interpreter instructions
50. How may switches are used to construct a 3-to 3-cycloconverter?
12
18
51. How many bits are used in data bus of 8085?
52. A register in the microprocessor that keeps track of the answer or result of any arithmatic or logic operation is the:
Stack pointer
Program counter
Instruction pointer
Accumulator
53. Ready pin of a Microprocessor is used:
To indicate that the µ is ready to receive I/P
To indicate that the µ is ready to receive O/P
To introduce wait states
To provide direct memory access
54. In which T-state does the CPU sends the address to memory or I/O the ALE signal for demultiplexing:
T1
T2
T3
T4
55. is equivalent
ABC
A B C
A. B. C.
56. The figure of merit is minimum
I2L
NMOS
ECL
TTL
57. In a thyristor, holding current
More than latching current
Less than latching current
Equal to latching current
Cannot compare with latching current
58. The PIV of a half wave rectifier circuit with a shunt capacitor filter
(a) 2V m
V m
V 2
3Vm
59. The ripple factor of a Power supply is a measure
Its filter efficiency
Its voltage regulation
Diode rating
Purity of Power output
60. In a three phase half wave rectifier, each diode conducts for a duration
30°
60°
120°
180°
61. A step up chopper has V as the source voltage and a as the duty cycle. The output voltage s for this chopper is given
Vs
None of these
62. In single pulse modulation of PWM inverter, third harmonic can be eliminated if pulse width is equal
30°
60°
120°
None of these
63. In dc chopper, the waveforms for input and output voltage are respectively:
Discontinuous, Continuous
Both continuous
Both discontinuous
Continuous, discontinuous
64. If in a rectifier the ripple voltage is 150 mV and the dc value is 15V, then ripple factor is given
0.01
0.02
0.001
0.002
65. If two ends of rods are to be welded, the method of welding
Spot welding
Projection welding
Seam welding
Butt welding
66. A three phase diode bridge rectifier is fed from a 400V RMS, 50Hz, three phase AC source. If the load is purely resistive, then peak instantaneous voltage is equal
400 V
400 V
400 route2/3v
400/ route3 V
67. In a 3-ph bridge inverter with 180° conduction, the number of switches that are at any instant of time
68. A 1-ph full bridge inverter can have load commutation only if the load
R-L
underdamped
overdamped
critically damped
69. A 3-ph induction motor under dc dynamic braking work
Induction generator
dc generator
dc motor
synchronous generator
70. A chopper circuit is operating on TRC principle at a frequency of 2kHz on 230 V supply. If the load voltage is 184V, the on time and off time (Toff of chopper are respectively:
Ton=0.3 msec, Toff=0.2 msec
Ton =0.38 msec, Toff=0.12 msec
Ton =0.2 msec, Toff=0.3 msec
Ton =0.4 msec, Toff=0.1 msec
71. The number of terms in a logic function of three variables are:
72. Which of the following is an invalid state in Binary coded Decimal counter:
1 0 0 0
1 0 0 1
0 0 1 1
1 1 0 0
73. Which of the following is a sequential circuit?
AND gate
NAND gate
Bistable multivibrator
EX-OR gate
74. The output X of the OR gate show in figure
<img src='./qimages/3399-74.jpg'>
0
2
3
75. The Boolean expression A is equal
1
B
A
A+B
76. If the J-K Flip flop's output is zero, then in order to change its output to the input combination
J K X
J K X
J K=1
J K 0
77. How many 3-line to 8-line decoders are required for a 1 of 32 decoder?
78. The output Y of the logic circuit given below
X
79. When a BJT is used as a switch, its mode of operation switches between:
Cut-off and active regions
Cut-off and saturation regions
Active and saturation regions
Different operating points in the active region
80. The most suitable gate for comparing two bit
AND gate
OR gate
NAND gate
EX-OR gate
81. Which of the following finds application in pocket calculator?
TTL
CMOS
ECL
Both and
82. Which has the lowest propagation delay time?
ECL
TTL
CMOS
DMOS
83. De Morgan's second theorem
A .
A
.
84. The minimum number of NOR gates A required to implement is equal
85. In a 6 bit Johnson counter sequence, there are a total of how many states or bit patterns?
12
24
86. The most powerful solid state microwave device
GUNN diode
IMPATT diode
MESFET
Varactor
87. The following wave does not exist in wave guides:
TE waves
TM waves
TEM
TE TEM
88. The characteristic Impedance of a lossless transmission line is given
Z
Z routeC/L
Z routeL/C
Z LC
89. The characteristic impedance of a cable is about:
300 omegha
50
90. As frequency is increased, the skin effect:
Increases
Decreases
Remains the same
Either or
91. The most noise immune system
SSB
PCM
PDM
PWM
92. Human ears can detect sound intensity of order
10-4 W/m2
10-8 W/m2
10-13 W/m2
10-18 W/m2
93. An AM wave is given by 0.5 cos 103 t 0.3 cos 104t. cos 106t), the modulation index of the envelope
0.5
0.58
0.3
0.8
94. A phase locked loop is a feedback circuit consisting of
Phase detector
Low pass filter
VCO
All of the above
95. An antenna has a resistance of 50 and an equivalent noise resistance of 30 . The noise figure in decibels
1.6 dB
2 dB
3.6 dB
6 dB
96. A carrier is modulated by two modulating waves A and B having modulation index of 0.6 and 0.8 respectively. The overall modulation index
1.0
0.7
0.2
1.4
97. In transistor radio receiver, the number of IF amplifier stages are:
98. For an ideal 3000Hz channel, S/N ratio
3
1.5
99. A waveguide section in microwave circuit acts
Low pass filter
Band pass filter
High pass filter
Band stop filter
100. Which TM mode in rectangular waveguide has lowest cut-off frequency?
TM11
TM01
TM10
TM21
101. A line has Z0=300 O . If ZL= 150 O reflection coefficient
0.5
0.333
-0.333
-0.5
102. Which of the following lines is non-radiating?
Open two wire
Co-axial
Both of the above
None of the above
103. Which of the following devices uses a helix?
Klystron Amplifier
Klystron Oscillator
TWT
Both and
104. A 6-pole, 50Hz, 3-phase induction motor has rotor resistance of 0.25 ohm and develops the maximum torque at 875 rpm. The rotor reactance and slip at the maximum torque respectively are:
2 0.125 pu
2 0. 25 pu
1 0. 25 pu
1 0.125 pu
105. The field excitation of 20A results in a short circuit armature current of 400A and open circuit terminal voltage of 2000V in an alternator. The magnitude of the internal voltage drop within the machine at a load current of 200A is
1 V
10 V
100 V
1000 V
106. What is the ratio of starting torque and maximum torque of a 3-phase, 50Hz, 4-pole induction motor when the maximum torque occurs at 1200 rpm?
0.384
0.421
0.5
0.6
107. A balanced three phase induction motor runs at slip If is the synchronous speed, what is the relative speed between the stator mmf and the rotor mmf?
s s
s
s
Zero
108. The supply voltage to a 3-phase induction motor is reduced by 10 percent. By what percentage will the maximum torque decrease?
12.1%
19.0%
21.0%
40.0%
109. Wide speed control range of three phase squirrel cage induction motor is obtained
Variable voltage constant frequency control method
Slip power recovery method
Pole changing method
Constant voltage to frequency ratio method
110. A 6-pole, 3-phase alternator running at 1000 rpm supplies to an 8-pole, 3-phase induction motor which has a rotor current of frequency 2 Hz. The speed at which the motor operates
1000 rpm
960 rpm
750 rpm
720 rpm
111. A synchronous motor is operating on no load at unity power factor, if the field current is increased, the power factor will become:
Leading and the stator current will decrease
Lagging and the stator current will increase
Lagging and the stator current will decrease
Leading and the stator current will increase
112. A synchronous motor is operated from a bus voltage of 1.0 pu and is drawing 1.0 pu zero power factor leading current. Its synchronous reactance is 0.5 pu What is the excitation emf of the motor?
0.5
1.0
1.5
2.0
113. Damper in a large generator is used
Increase stability
Reduce Voltage fluctuation
Reduce frequency fluctuation
All above
114. A 10 pole AC generator rotates at 1200 rpm. The frequency of AC voltage in cycle per second will
120
110
100
50
115. Speed of a repulsion motor at No load
Low
Very low
High
Dangerously high
116. What is the ratio of No-load speed to full load speed of a 200 kVA, 12 pole, 220V, 3 phase, 60 Hz synchronous motor?
1
1.1
1.21
Infinite
117. The motor used in household refrigerators
dc series motor
dc shunt motor
universal motor
Single phase induction motor
118. An ideal transformer does not-change:
Voltage
Power
Current
None of the above
119. The slip of an induction motor normally does not depend
Rotor speed
Synchronous speed
Shaft torque
Core-loss component
120. Skewing is used in induction motors in order to reduce torque due
Time harmonics
Space harmonics
Slot harmonics
Reverse rotating fields
121. Which type of motor is most suitable for computer printer device?
Reluctance motor
Hysterisis motor
Shaded pole motor
Stepper motor
122. In a circle diagram of a three phase induction motor the point where tangent to the circle is parallel to the horizontal line represents:
Maximum torque
Maximum output power
Maximum input
Stator loss
123. In a split phase motor, the ratio of number of turns for starting winding to that for running winding
2.0
More than 1.0
1.0
Less than 1.0
124. A 3 3 stack, variable reluctance step motor has 20 poles on each rotor and stator stack. The step angle of this step motor
3°
6°
9°
18°
125. Which of the following is an unexcited single phase synchronous motor?
A.C. series motor
Reluctance motor
Universal motor
Repulsion motor
126. A 60 Hz induction motor runs at 1150 rpm, its synchronous speed
1300 rpm
1500 rpm
1200 rpm
1000 rpm
127. The common type of servo motor is different from normal induction motor as it has:
Lower rotor resistance
Higher rotor resistance
Higher power rating
Larger inertia
128. When a 3-phase alternator is suddenly short circuited at its terminals, the initial value of short circuit current is limited by which one of the following?
Subtransient reactance
Transient reactance xd
Synchronous reactance x s
Sum of xd xd and x s
129. The domestic mixer uses an electric motor of type:
Universal motor
Shaded pole motor
Synchronous motor
Induction motor
130. The rotor power output of three phase induction motor is 15kW. The rotor copper loss at a slip of will
600W
625W
650W
700W
131. The change in speed of a 3 f induction motor from No load to full load is about:
15%
50%
132. A three phase induction motor takes A ampere on full load at a power factor of cos f . The component responsible for producing magnetization is approximately:
A sin
A tan
A cos
A cos
133. Synchronous motor can run
Leading power factor
Lagging power factor
Unity power factor
Any of above
134. As the load on a synchronous motor is increased, the torque angle:
Increases
Decreases
Remains same
None of these
135. If a dc series motor is connected to AC supply, then:
It will not run
It will run
It will burn out
It will pulsate
136. Which type of connection is employed for current transformers for the protection of star- delta connected 3-phase transformer
Delta Delta
Star Star
Star Delta
Delta Star
137. The relay used for protection of high voltage a.c. transmission line against power swing
Instantaneous overcurrent relay
Impedance relay
Mho relay
Reactance relay
138. The restriking voltage in circuit breaker is measured
RMS value
Peak value
Instantaneous value
Average value
139. The most suitable circuit breaker for interrupting short line fault without resistance switching
Minimum oil circuit breaker
SF6 circuit breaker
Bulk oil circuit breaker
Air blast circuit breaker
140. Which one of the following is not a routine test of a circuit breaker?
Short circuit test
Dielectric test
Thermal test
DC resistance voltage drop test
141. What is the approximate value of the surge impedance loading of a 400kV, 3-phase, 50Hz overhead single circuit transmission line?
230 MW
400 MW
1000 MW
1600 MW
142. How many relays are used to detect interphase fault of a three phase system?
One
Two
Three
six
143. Circuit breaker is used for which of the following:
Voltage control
Power control
Frequency control
Over current protection
144. Which is preferred type of C.B to be installed in EHV system?
Vacuum C.B.
Air blast C.B.
Bulk oil C.B.
None of these
145. If the fault current is 2000 the relay setting is 50% and CT ratio is 400 the plug setting multiplier will
25 A
15 A
50 A
10 A
146. In an open ended line, the reflection coefficient of current
147. Resistance switching is normally employed
All breakers
Bulk oil breakers
Minimum oil breakers
Air blast breakers
148. In an Indoor substation for 220 kV, the circuit breakers will be of the type:
Oil
Air break
SF6
Vacuum
149. The term critical clearing time in protection of Power system is related
Reactive power limit
Steady state stability limit
Short circuit current limit
Transient stability limit
150. The rate of rise of restriking voltage depends
Resistance and inductance of the system only
Inductance of system only
Capacitance of the system only
Inductance and capacitance of the system only
151. A relay with inherent directional characteristic
Mho relay
Impedance relay
Reactance relay
Differential relay
152. Loss of excitation in an alternator can be detected by using:
Earth fault relay
IDMT relay
Reactance relay
Offset Mho relay
153. In a circuit breaker, the time duration form the instant of the fault to the extinction of arc is known
Total clearing time
Operation time
Protection time
Recovery time
154. The making current of a 3-phase circuit breaker with rating 2000 MVA, 33kV will
35 kA
50 kA
70 kA
89 kA
155. If the percentage reactance of the system upto the fault point is 20% and the base kVA is 10,000 then the short circuit VA
10 MVA
20 MVA
50 MVA
60 MVA
156. Impedance relay can be used for:
Earth fault only
Phase fault only
Both earth and phase fault
None of these
157. Merz Price Protection is used to protect:
Transmission line and transformers
Transformers and generators
Motors only
Transformers only
158. For a fault at terminals of the synchronous generator, the fault current is maximum for
3 Phase fault
3 to ground fault
Line to ground fault
Line to line fault
159. A three phase, 33kV oil circuit breaker is rated for 1200 2000 MVA, 3s. The symmetrical breaking current
1200A
3600 A
35 kA
104.8 kA
160. A thermal protection switch provides protection against:
Over load
Under voltage
Short circuit
Over voltage
161. Using Euler's method, the value of y after 1st iteration for the differential equation
with y=1 when x=0 and h=0.1
1.0
1.1
1.2
Cannot be obtained due to insufficient data
162. The circuit shown
<img src='./qimages/3399-162.jpg'>
Inverting amplifier
Non inverting amplifier
Voltage to current convertor
Voltage follower
163. A unit positive step is applied at the input of the circuit shown below. After 15 seconds, the output Vo will
<img src='./qimages/3399-163.jpg'>
164. For the following analog simulation, the dynamic equation
<img src='./qimages/3399-164.jpg'>
165. Which one of the following methods is used for numerical integration?
Newton Raphson method
Lagrange's method
Trapezoidal rule
None of above
166. For solving equation x3-3x+1 0 by Newton Raphson method, the initial guess be next estimate x1 will
0.212
0.333
0.40
0.425
167. An op-Amp has a slew rate of 5V/ µ s. The largest sine wave o/p voltage possible at a frequency of 1MHz
10 V
5 V
V
5 2 V
168. To fit y=abx in linear form
y=cx+a
y=ax+c
ay=cx
y=x where x=xb
169. Interpolation is a technique of estimating the value of a function for any:
Minimum value of a variable
Intermediate value of a variable
Maximum value of a variable
None of these
170. A differential amplifier has a differential gain of 20,000 and CMRR=80db. The common mode gain is given
2
1
1/2
2.5
171. An ideal differential amplifier has CMRR equaling:
Unity
Zero
172. Using Runge Kutta fourth order method, the approximate value of y when x 0.2, given
that x+y when x 0 is given
1.3428
1.2421
1.2428
1.4345
173. The general solution of the differential equation
dx/dy x/y x/tany
sin
sin
cos
cos
174. Which of the following formula is most accurate for numerical integration?
Simpson's rule
Trapezoidal rule
Weddle's formula
Gauss's Quadrature formula
175. The value of
<img src='./qimages/3399-175.jpg'>
176. The differential equation t2 0 is called:
Fourier's equation
Laplace equation
Bessel's equation of index n
Hamiltonian equation
177. Effective address is calculated by adding or subtracting displacement value
Intermediate address
Relative address
Absolute address
Base address
178. If two stages with noise figure F1 and F2 and gains G1 G2 are cascaded, the resultant noise F will
179. The input resistance Ri and output resistance Ro of an Ideal current amplifier in Ohms are:
0 and 0
0 and infinity
and 0
and
180. If the input to an antilog amplifier is the output is proportional
<img src='./qimages/3399-180.jpg'>