Veer Surendra Sai University of Technology
Name of the Candidate: ____________________________________Roll No.: ______________
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Signature of Candidate
Signature of Invigilator
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Silicon steel is preferred for transformer core because
(a) It decreases the permeability of the core
(b) It reduces both eddy current and hysteresis loss
(c) It reduces resistivity of the core
(d) It decreases the tensile strength
A 4 KVA, 400/200V single phase transformer has resistance of 0.02 p.u. and reactance of
0.06 p.u. What are its resistance and reactance referred to h.v. side?
(a) 0.8 ohm and 2.4 ohm
(b) 0.2 ohm and 0.6 ohm
(c) 0.08 ohm and 0.24 ohm
(d) 1 ohm and 3 ohm
The frequency of the impressed voltage of a transformer is increased keeping its magnitude
fixed. Its
(a) Hysteresis loss increases and eddy current loss decreases
(b) Hysteresis loss decreases and eddy current loss increases
(c) Hysteresis loss increases and eddy current loss remains constant
(d) Hysteresis loss and eddy current loss both increases
A transformer has a percentage resistance of 1 % and percentage reactance of 4 %. Its
voltage regulation at power factor of 0.8 lagging and 0.8 leading are respectively
(a) 3.2 % and -1.6 %
(b) 6 % and -4 %
(c) 4.8 % and -3.2 %
(d) None of these
A three phase transformer with delta-connected h.v. side and star-connected l.v. side can
have the following symbol which also indicates the phase displacement
(a) Dy1 or Dy11
(b) Dy0 or Dy6
(c) Dy1 only
(d) Dy11 only
A 4 pole d.c. generator with wave wound armature has 50 slots with 20 conductors per slot.
The induced e.m.f. is 340 volts and the speed is 8500 r.p.m. The flux per pole will be
7.
8.
9.
10.
11.
12.
13.
(a) 2.4 mWb
(b) 1.2 mWb
(c) 14 mWb
(d) 21 mWb
If the armature current of a d.c. motor is increased keeping the field flux constant, then the
developed torque
(a) Decreases in inverse proportion
(b) Remains constant
(c) Increases proportional to the square of the current
(d) Increases proportionally
In a d.c. machine, the polarity of the interpole is
(a) Same as that of the main pole behind for generators and that of the main pole ahead for
the motors
(b) Same as that of the main pole ahead for both generators and the motors
(c) Same as that of the main pole ahead for generators and that of the main pole behind for
the motors
(d) Same as that of the main pole behind for both generators and the motors
A d.c. motor is run successively as a shunt motor, differential compound motor and
cumulative compound motor with the same no-load speed. They can be arranged in the
following order of decreasing full-load speeds
(a) Cumulative compound, differential compound, shunt
(b) Cumulative compound, shunt, differential compound
(c) Shunt, differential compound, cumulative compound
(d) Differential compound, shunt, cumulative compound
A d.c. shunt motor has two additional resistances R1 and R2 in the field circuit and armature
circuit respectively. The starting armature current can be kept to a minimum by keeping
(a) R1 maximum and R2 maximum
(b) R1 minimum and R2 maximum
(c) R1 maximum and R2 minimum
(d) R1 minimum and R2 minimum
In a synchronous generator in order to eliminate the fifth harmonic the chording angle
should be.
(a) 90
(b) 180
(c) 270
(d) 360
If the diameter and length of the stator bore of a high-speed turbo alternator and a low-speed
hydel generator of identical rating are compared, then
(a) The turbo alternator has larger diameter and larger length
(b) The turbo alternator has smaller diameter and smaller length
(c) The turbo alternator has larger diameter and smaller length
(d) The turbo alternator has smaller diameter and larger length
In relation to the synchronous machines, which one of the following statements is false
(a) In salient pole machines, the direct-axis synchronous reactance is greater than the
quadrature-axis synchronous reactance
(b) The damper bars help the synchronous motor self start
(c) Short circuit ratio is the ratio of the field current required to produce the rated voltage on
open circuit to the rated armature current
14.
15.
16.
17.
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(d) The V-curve of a synchronous motor represents the variation in the armature current
with field excitation, at a given output power
At a slip of 4 %, the maximum possible speed of a 3-phase squirrel cage induction motor is
(a) 2800 r.p.m (b) 3000 r.p.m.
(c) 1500 r.p.m
(d) 1440 r.p.m.
Rotor core loss of a 3-phase induction motor are small because
(a) Rotor is laminated
(b) Rotor frequency is very small
(c) Rotor flux density is very small
(d) All of the above
The ratio of starting torque in auto-transformer starting with x % tapping to that in direct-online starting of a 3-phase induction motor is equal to
(a) x
(b) 1/x
(c) x
(d) x2
In a 3-phase induction motor, speeds higher than the synchronous speed can be obtained by
(a) Variation of supply voltage
(b) Rotor slip power control
(c) Variation of supply frequency
(d) Variation of rotor resistance
If the 12 Ω resistor draws a current of 1A as shown in the figure below, the value of
resistance R is:
(a) 4 Ω
(b) 6 Ω
(c) 8 Ω
(d) 12 Ω
19. A sinusoidal source of voltage V and frequency f is connected to a series circuit of variable
resistance R and a fixed reactance X. The locus of the tip of the current phasor I as R is
varied from 0 to infinity is:
(e) A semicircle with a diameter of V/X
(f) A straight line with a slope of R/X
(g) An ellipse with V/R as major axis
(h) A circle of radius R/X and origin at (0, V/2)
20. A D.C. shunt motor running at 1200 rpm, when excited with 220 V D.C. Neglecting losses
and saturation, the speed of the motor when connected to a 175 D.C. supply is:
(a) 750 rpm
(b) 900 rpm
(c) 1050 rpm
(d) 1200 rpm
21. The low voltage winding of a 400/230 V, single phase, 50 Hz transformer is to be connected
to a 25 Hz supply. The supply voltage should be:
(a) 230 V
(b) 460 V
(c) 115 V
(d) 400 V
22. The armature of a single phase alternator is wounded with T single turn coils distributed
uniformly. The induced voltage in each turn is 2 Volts (rms). The emf of the whole winding
is:
(a) 2 T Volt
(b) 1.11 T Volt
(c) 1.414 T Volt
(d) 1.273 T Volt
23.
(a)
(b)
(c)
(d)
24.
In an induction motor, if the air gap is increased, then
Speed will reduce
Efficiency will improve
Power factor will be lower
All the above
The voltage phasor of a circuit is 10150 V and the current phasor is 2  450 A. The
active and reactive powers in the circuits are:
(a) 10W, 17.32VAR (b) 5W, 8.66VAR
25.
(c) 20W, 60VAR
(d) 20 2 W, 10 2 VAR
For a fixed value of complex power flow in a transmission line having a sending end
voltage V, the real power loss will be proportional to:
(b) V2
(a) V
26.
(c) 1/V2
(d) 1/V
A cable has the following characteristics. L = 0.201 µH/m and C= 196.2 pF/m. The
velocity of wave propagation through the cable is:
(a) 32 m/(µ-s)
27.
(b) 159.24 m/s
(c) 0.0312 m/s
(d) 159.24 m/(µ-s)
If the fault current is 2000 A, the relay setting is 50% and CT ratio is 400:5, the plug
setting multiplier will be:
(a) 25 A
28.
(b) 15 A
(c) 50 A
(d) 10 A
The three-terminal voltage regulator is connected to a 10 ohm load resistor as shown in
figure below. If Vin is 10 V, what is the power dissipated in the transistor?
(a)
29.
0.6 W
(b) 2.4 W
(c) 4.2 W
(d) 5.4 W
In the circuit shown below, the diode connects the ac source to a pure inductor of
inductance L. the diode conducts for
(a) 900
30.
(b) 1800
(c) 2700
The transfer function of the system described by
(d) 3600
d2y
dt 2

dy du

 2u with u as input and y
dt dt
as output is :
(a)
31.
( s  2)
(b)
( s 2  s)
(a) 0.143
(c)
2
(s 2  s)
(d)
2s
(s 2  s)
1
. The maximum overshoot is:
s(s  1)
(b) 0.153
(c) 0.163
(d) 0.173
For the equation s3  4s 2  s  6  0 , the number of roots in the left half of s-plane will be:
(a) zero
33.
(s 2  s)
Consider the unit step response of a unity feedback control system whose open loop
transfer function is G(s) 
32.
( s  1)
(b) one
(c) two
(d) three
An ammeter has a current range of 0-5 A, and its internal resistance is 0.02 Ω. In order to
change the range to 0-25 A, we need to add a resistance of:
(a)
(b)
(c)
(d)
34.
0.08 Ω in series with the meter
1.0 Ω in series with the meter
0.04 Ω in parallel with the meter
0.05 Ω in parallel with the meter
Assume that the op-amp shown below is ideal. The output voltage V0 is:
(a)4 V
(b) 6 V
(c) 7.5 V
(d) 12.12 V
35.
The content of the accumulator in an 8085 microprocessor is altered after the execution
of the instruction:
(a) CMP C
(b) CPI 3A
(c) ANI 5C
(d) ORA A
36.
The energy stored in the magnetic field of solenoid 30 cm long and 3 cm diameter wound
with 1000 turns of wire carrying a current of 10 A is:
(a) 0.015 J
37.
(a)
(b) 0.15 J
(c) 0.5 J
(d) 1.15 J
The Laplace transform of (t 2  2t ) u(t  1) is:
2 s 2 s
e  e
s3
s2
(b)
2  2s 2  s
e

e
s3
s2
(c)
2 s 1 s
e  e
s
s3
(d) none of the above
38. When a power BJT is used as power electronics switch which of the following is true
(a) It operates in Active and Saturation region
(b) It operates only in Saturation region
(c) It operates in Active and Cut-off region
(d) It operates in Saturation and Cut-off region
39. Specification sheet of an SCR specifies average on state current rating as 20 A for
conduction angle of 120 degree, then for 60 degree conduction angle the same rating is
(a) 20 A
(b) 10 A
(c) less than 20 A
(d) 40 A
40. A single phase full wave mid-point converter uses a 230/200 V transformer with centre tap
on secondary side. The P.I.V per thyristor is
(a)100 V
(b) 141.4 V
(c) 200 V
(d) 282.8 V
41. If a diode is connected in anti-parallel with a thyristor, then
(a) Both turn-off power loss and turn-off time decreases
(b) Turn-off power loss decreases but and turn-off time increases
(c) Turn-off power loss increases but and turn-off time decreases
(d) None of the above
42. In a duel converter, the circulating current
(a) Allows smooth reversal of load current, but increases the response time
(b) Does not allow smooth reversal of load current, but reduces the response time
(c) Allows smooth reversal of load current with improved speed of response
(d) Flows only if there is no interconnecting inductor
43. For thyristors, pulse triggering is preferred to dc triggering because
(a) G a t e d i s s i p a t i o n i s l o w
(b) P u l s e s y s t e m i s s i m p l e r
(c) Triggering system is required for a very short duration
(d) A l l o f t h e s e
44. In a thyristor, ratio of latching current to holding current is
(a) 0.4
(b) 1.0
(c) 2.5
(d) None of these
45. In a GTO, anode current begins to fall when gate current is
(a) Negative peak at time t = storage time ts
(b) Negative peak at time t = 0
(c)Just begins to become negative at t = 0
(d) None of these
46. The MOSFET switch in its on-state may be considered equivalent to
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48.
49.
50.
51.
52.
53.
54.
55.
(a)Resistor
(b) Inductor (c) Capacitor (d) Battery
In dc choppers, the waveforms for input and output voltages are respectively
(a) Discontinuous, continuous (b) Both discontinuous
(c) Both continuous
(d) Continuous, discontinuous
In power station practice "spinning reserve" is
(a) Reserve generating capacity that is in operation but not in service
(b) Reserve generating capacity that is connected to bus and ready to take the load
(c) Reserve generating capacity that is available for service but not in operation
(d) Capacity of the part of the plant that remains under maintenance
Transmission efficiency increases as
(a) Voltage and power factor both increase
(b) Voltage and power factor both decrease
(c) Voltage increases but power factor decreases
(d) Voltage decreases but power factor increases
Skin effect results in
(a) Reduced effective resistance but increased effective internal reactance of the conductor
(b) Increased effective resistance but reduced effective internal reactance of. the conductor
(c) Reduced effective resistance as well as effective internal reactance
(d) Increased effective resistance as well as effective internal reactance
The corona is considerably affected by which of the following
(a) Size of the conductor
(b) Shape of the conductor
(c) Surface condition of the conductor
(d) All of the above
The phenomenon of rise in voltage at the receiving end of the open-circuited or lightly
loaded line is called the
(a) Skin effect
(b) Proximate effect
(c) Ferranti effect
(d) Raman effect
The characteristic impedance of a transmission line depends upon
(a) Shape of the conductor
(b) Surface treatment of the conductors
(c) Conductivity of the material
(d) Geometrical configuration of the conductors
A generating station has a maximum demand of 50 Mw, a load factor of 60%, a plant
capacity factor of 45% and if the plant while running as per schedule, were fully loaded. The
daily energy produced will be
(a) 720 MW
(b) 400 MW (c) 500 MW
(d) 600 MW
Which one of the following statement is not correct for the use of bundled conductors in
transmission lines?
(a) Control of voltage gradient
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
(b) Reduction in corona 1088
(c) Reduction in radio interference
(d) Increase in interference with communication lines
By which of the following methods string efficiency can be improved?
(a) Using a guard ring
(b) Grading the insulator
(c) Using long cross arm
(d) Any of the above
For an existing ac transmission line, the string efficiency is 80%, if dc voltage is supplied
for the same set up, the string efficiency will be
(a) < 80%
(b) 80%
(c) 90%
(d) 100%
Series capacitive compensation in EHV transmission lines is used to
(a)Improve the stability of the system
(b) Reduce the line loading
(c) Reduce the voltage profile
(d) Improve the protection of the line
In load flow analysis, the load connected at a bus is represented as
(a) Constant current drawn from the bus
(b) Constant impedance connected at the bus
(c) Voltage and frequency dependent source at the bus
(d) Constant real and reactive drawn from the bus
In a HVDC transmission line
(a) It is necessary for the sending end and receiving end to be operated in synchronism.
(b) The effects of inductive and capacitive reactances are greater than in an AC transmission
line of the same rating.
(c) There are no effects due to inductive and capacitive reactances.
(d) Power transfer capability is limited by stability considerations.
The steady-state stability limit of a synchronous generator can be increased by
(a) An increase in its reactance
(b) An increase in the excitation of the machine
(c) A decrease in the moment of inertia of the machine
(d) An increase in the moment of inertia of the machine
For a fault at the terminal of a synchronous generator, the fault current is maximum for a
(a) 3-phase fault (b) 3-phase to ground fault (c) line to ground fault (d) line to line fault
Reactance relay is normally preferred for protection against
(a) Earth faults (b) Phase faults (c) Open circuit faults (d) None of these
The use of high-speed circuit breakers
(a) Decreases the system stability
(b) Improves the system stability
(c) Reduces the short circuit current
(d) Increases the short circuit current
The X:R ratio of 220 kV line as compared to 400 kV line is
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
(a) Smaller
(b) Greater
(c) Equal
(d) It could be anything
Which of the following relays is used on long transmission lines?
(a) Impedance relay (b) Mho's relay (c) Reactance relay (d) None of the above
Solar constant is
(b) 1.4 Wm-2 (c) 1.40 kWm-2
(d) 1.4 MWm-2
(a) 140 Wm-2
What is the kinetic energy of 1 cubic meter of air moving at the speed of 10 m/s? The
density of air is 1.2 kg/m3
(a) 12 J
(b) 120 J
(c) 60 J
(d) 6 J
Which of the following problems is associated with the burning of coal?
(a) Acid rain
(b) Carbon dioxide emissions
(c)Ash with toxic metal impurities
(d) All of these
What type of energy is derived from heated groundwater?
(a) Solar energy
(b) Geothermal energy
(c) Hydroelectric energy
(d) Photo-voltaic
In a common emitter amplifier, the unbypassed emitter resistance provides
(a) Voltage-shunt feedback
(b) Current-series feedback
(c) Negative-voltage feedback
(d) Positive-current feedback
An ideal OPAMP is used to make an inverting amplifier. The two input terminals of the
OPAMP are at the same potential because
(a) The two input terminals are directly shorted internally
(b) The input impedance of the OPAMP is infinity
(c) The open loop gain of the OPAMP is infinity
(d) The input impedance of the OPAMP is zero
In an RC-coupled common emitter amplifier, which of the following is true?
(a) Coupling capacitance affects the hf response and bypass capacitance affects the If
response
(b) Both coupling capacitance and bypass capacitance affect the If response only
(c) Both coupling capacitance and bypass capacitance affect the hf response only
(d) Coupling capacitance affects the If response and bypass capacitance affects the hf
response
The number of comparisons carried out in a 4-bit flash-type A/D converter is
(a) 16
(b) 15
(c) 4
(d) 3
A switch mode power supply operating at 20kHz to 100 kHz range uses as main switching
element
(a) MOSFET
(b) Thyristor
(c) Triac
(d) UJT
The number of comparisons needed in a parallel conversion type 8-bit A/D converter is
77.
78.
79.
80.
81.
82.
83.
84.
85.
86.
(b) 8
(b) 16
(c) 255
(d) 256
A major advantage of active filter is that they can be realized without using
(b) Inductors
(c) Resistors
(d) Capacitors
(a) OPAMPS
A NAND gate is equivalent to an AND gate plus a _____gate put together
(a) NOR
(b) XOR
(c) AND
(d) NOT
Digital circuits mostly use
(a) Diodes
(b) Bipolar transistors
(c) Diode and Bipolar transistors
(d) Bipolar transistors and FETs
When an op amp is not saturated, the voltage at the noninverting and inverting inputs are
(a) Almost equal
(b) Much different
(c) Equal to the output voltage
(d) Equal to ±15V
An ideal op amp is an ideal
(a) Voltage controlled voltage source
(b) Voltage controlled current source
(c) Current controlled current source
(d) Current controlled voltage source
If the HLT instruction of a 8085 microprocessor is executed
(a) The microprocessor is disconnected from the system bus till the Reset is pressed
(b) The microprocessor enters into a Halt state and buses are tri-stated
(c) The microprocessor halts execution of the programme and returns to monitor
(d) The microprocessor reloads the programme from the locations 0024 and 0025 H
The contents of the accumulator in an 8085 microprocessor is altered after the execution of
the instruction
(b) CMPC
(b) CPI 3A
(c) ANI 5C
(d) ORA A
One of the main feature that distinguish microprocessors from micro-computers is
(a) Words are usually larger in microprocessors
(b) Words are shorter in microprocessors
(c) Microprocessor does not contain I/O devices
(d) Exactly the same as the machine cycle time
The technique of assigning a memory address to each I/O device in the computer system is
called
(a) Memory-mapped I/O
(b) ported I/O
(c) dedicated I/O
(d) wired I/O
I/O mapped systems identify their input/output devices by giving them a(n)
(a) 8-bit port number
(b) 16-bit port number
(c) 8-bit buffer number
(d) 8-bit instruction
87. Noise with uniform power spectral density of N0W/Hz is passed through a filter H (w) = 2
exp (-jwtd) followed by an ideal low pass filter of bandwidth B Hz. The output noise power
in Watts is
(a) 2N0B
(b) 4N0B
(c) eN0B
(d) 16 N0B
88. The cascade amplifier is a multistage configuration of
(a) CC-CB
(b) CE-CB
(c) CB-CC
(d) CE-CC
89. A device with input x(t) and output y(t) is characterized by: y(t) = x2(t). An FM signal with
frequency deviation of 90 kHz and modulating signal bandwidth of 5 kHz is applied to this
device. The bandwidth of the output signal is
(a)370 kHz
(b) 190 kHz
(c) 380kHz
(d) 95kHz
90. An AM signal is detected using an envelope detector. The carrier frequency and modulating
signal frequency are 1 MHz and 2 kHz respectively. An appropriate value for the time
constant of the envelope detector is
(a) 20 msec
(b) 500 msec
(c) 0.2 msec
(d) 1 msec
91. AM and FM are examples of ________ conversion
(a) Digital-to-digital
(b) Digital-to-analog
(c) Analog-to-analog
(d) Analog-to-digital
92. An AM demodulator can be implemented with a linear multiplier followed by a _____ filter.
(a) low-pass
(b) high-pass
(c) band-pass
(d) band-stop
93. The intermediate frequency in a standard AM receiver is
(a)55 Hz
(b) 455 Hz
(c) 4.55 Hz
(d) None of these
94. In a Pulse code modulation system, if the code word length is increased from 6 to 8 bits, the
signal to quantization noise ratio improves by the factor
(b) 12
(c) 16
`(d) 8
(a) 8/6
95. The shared block of a receiver that consists of AM and FM signals is the
(a) Mixer
(b) IF amplifier
(c) discriminator
(d) Audio amplifier
ACT Qtn.
1. In commercial FM broadcasting, the maximum frequency deviation is normally
A) 5 KHz
B) 15 KHz
C) 75 KHz
D) 200 KHz
2. The most common device used for detection in radio receivers is A) Amplifier
B) triode
C) diode
D) transistor
3. Amplitude modulation is used for broadcasting because
A) It is more noise immune than other modulation systems
B) Compared with other systems it requires less transmitting power
C) Its use avoids receiver complexity
D) No other modulation system can provide the necessary bandwidth for high fidelity
4. In a radio receiver the IF amplifier
A) Is tuned above the stations incoming frequency
B) Amplifies the output of local oscillator
C) Is fixed tuned to one particular frequency
D) Can be tuned to various isolate frequencies
5. A low pass filter circuit is basically A) A differentiating circuit with low time constant
B) A differentiating circuit with large time constant.
C) An integrating circuit with low time constant.
D) An integrating circuit with large time constant.
6. The i/p SNR of system is 50 and the o/p SNR is 5 the noise figure is A) 250
B) 55
C) 10
D) 45
7. When an A.M. broadcast radio transmitter radiates 10 kW power when the modulation percentage is 60 then the
power of the carrier isA) 5.00 kW
B) 7.69 kW
C) 8.47 kW
D) 9.17 kW
DCT Qtn.
8. In delta Modulation, the number of levels used is
a) 1
b) 2
c) 8
d) 256
9. A signal having uniformly distributed amplitude in the interval (-v, +v) is to be encoded using PCM with
uniform quantization. The signal to quantizing noise ratio is determined by the-
a) Dynamic range of the signal
b) Number of quantizing level
c) Sampling rate
d) Power spectrum of signal.
10. In a PCM system, the numbers of quantization level are 16 and the maximum signal frequency is 4KHz. The bit
transmission rate is-
a) 64 K bits / sec
b) 32 bits / sec
c) 32 K bits /sec
d) 16K bits /sec
11. Companding is used
a) In delta modulator to combat noise
b) To limit amplitude in PCM transmitters.
c) In PCM to reduce the SNR
d) To protect small signals in PCM from quantizing distortion
12. In a PCM system with uniform quantization, increasing the number of bits from 8 to 9 will reduce the quantization
noise power by a factor of
a) 9
b) 8
c) 4
d) 2
13. The Hartley-Shannon theorem sets a limit on the
a) Highest frequency that may be sent over a given channel
b) Maximum capacity of a channel with a given noise level
c) Maximum number of coding levels in the channel with a given noise level
d) Maximum number of quantizing levels in a channel of a given bandwidth
14. If sampling time is less than the Nyquist interval, then
a) Bandwidth increases
b) Channel capacity increases
c) Guard time reduces
d) Simpler filters may be used to obtain the original signal
DSP Qtns
15. Two digital filters can be operated in cascade. Or, the same effect can be achieved by
a)adding their coefficients
b) multiplying their coefficients
c) convolving their coefficients
d) averaging their coefficients and then using a Blackman window
16. For the rectangular window function, the transition width of the main lobe is approximately (here M is
the length of the filter)
a) 4.pi.M
b) pi/4.M
c) pi.M/4
d) 4.pi/M
17. If the Nyquist rate for xa(t) is Ωs, what is the Nyquist rate for xa2(t)
a. 2Ωs
b. Ωs/2
c. Ωs
d. Ωs/4
18. If a continuous-time filter with an impulse response ha(t) is sampled with a sampling frequency of fs,
what happens to the cutoff frequency wcof the discrete-time filter as fs is increased?
a. wc increases
b. wc decreases
c. wc remains constant
d. wc depends upon fs
19. Which of the following best defines Nyquist Frequency?
a. Resonance frequency for the filtering circuit
b. The second Harmonic
c. The lower frequency limit of sampling.
d. The highest frequency of a given Analog signal
20. A continuous-time signal xa(t) is known to be uniquely recoverable from its samples xa(nTs) when Ts= 1
ms. What is the highest frequency in Xa( f )?
a. 500 Hz
b. 1000 Hz
c. 700 Hz
d. 5 KHz
Answers
1 – C,
8 – B,
15 – C,
2 – C,
9 – B,
16 – D,
3 – C,
10 – B,
17 – A,
4 – C,
11 – D,
18 – B,
5 – D,
12 – C,
19 – D,
6 – D,
13 – B,
20 – A
7 – C,
14 – D,
DEC
1)If (211) (152)x8 , then the value of base x is
(A) 6
( B) 5
(C) 7
(D) 9
2)11001, 1001 and 111001 correspond to the 2’scomplement representation of the following set ofnumbers
(A) 25, 9 and 57 respectively
(B) 6, 6 and 6 respectively
(C) 7, 7 and 7 respectively
(D) 25, 9 and 57 respectively
3)From a four-input OR gate the number of inputcondition, that will produce HIGH output are
(A) 1
(B) 3
(C) 15
(D) 0
4)If the X and Y logic inputs are available and theircomplementsX and Y are not available, the minimumnumber of
two-input NAND required to implementX ExorY is
(A) 4
(B) 5
(C) 6
(D) 7
5) Consider the given circuit
In this circuit, the race around
(A) does not occur
(B) occur when CLK =0
(C) occur when CLK=1 and A=B=1
(D) occur when CLK=0andA=B =0
Q-6) The output Yof a 2-bit comparator is logic 1 whenever the 2-bit input Ais greater
than the 2-bit input B. The number of combinations for which the output is logic 1, is
(A) 4 (B) 6(C) 8 (D) 10
Q-7) In the sum of products function f(X,Y ,Z)= ∑(2,3,4,5)the prime implicants are
(A) X Y, X Y
(B)
X Y, X Y Z , X Y Z
(C) X Y Z , X YZ, X Y
(D) X Y Z , X Y Z, X Y Z ,X Y Z
Q-8) The state transition diagram for the logic circuit shown is
(A)
(B)
(C)
(D)
Q-9) The output Yin the circuit below is always ‘1’ when
(A) two or more of the inputs P, Q, Rare ‘0’
(B) two or more of the inputs P, Q, R are ‘1’
(C) any odd number of the inputs P, Q, R is ‘0’
(D) any odd number of the inputs P, Q, R is ‘1’
Q-10)When the output Y in the circuit below is ‘1’, it implies that data has
(A) changed from 0 to 1 (B) changed from 1 to 0
(C) changed in either direction (D) not changed
Q-11)The logic function implemented by the circuit below is (ground implies logic 0)
(A) F=AND (P,Q) (B) F=OR(P,Q)
(C) F= XNOR (P,Q)(D) F=XOR( P,Q)
Q-12) The output of a 3-stage Johnson (twisted ring) counter is fed to a digital-to analog
(D/A) converter as shown in the figure below. Assume all the states of the counter
to be unset initially. The waveform which represents the D/A converter output VOis
(A)
(B)
(C)
(D)
Q-14) For the output Fto be 1 in the logic circuit shown, the input combination should
Be
(A) A=1, B=1,C=0(B) A=1,B=0,C=0
(C) A=0,B=1,C=0(D) A=0,B=0,C =1
Q-15) In the circuit shown, the device connected Y5 can have address in the range
(A) 2000-20FF (B) 2D00-2DFF
(C) 2E00-2EFF (D) FD00-FDFF
Q-16)Assuming that the flip-flop are in reset condition initially, the count sequence
observed at QA, in the circuit shown is
(A) 0010111... (B) 0001011...
(C) 0101111... (D) 0110100....
Q-17) The Boolean function realized by the logic circuit shown is
(A) F=∑m (0,1, 3, 5, 9,10,14) = (B) F=∑m(2,3,5,7,8,12,13)
(C) F=∑m(1, 2, 4, 5, 11, 14, 15) (D) F=∑m (2,3 ,5 ,7 ,8 ,9 ,12 )
Q-18)If X= 1in logic equation [X+Z{ Y +( Z +X Y )}] { X + X (X+Y)}=1, then
(A) Y=Z
(C) Z =1
(B) Y= Z
(D) Z= 0
Q-19)What are the minimum number of 2- to -1 multiplexers required to generate a 2input AND gate and a 2- input Ex-OR gate
(A) 1 and 2 (B) 1 and 3
(C) 1 and 1 (D) 2 and 2
Q-20) Refer to the NAND and NOR latches shown in the figure. The inputs (P 1,P2)for
both latches are first made (0, 1) and then, after a few seconds, made (1, 1). The
corresponding stable outputs ( Q1, Q2) are
(A) NAND: first (0, 1) then (0, 1) NOR: first (1, 0) then (0, 0)
(B) NAND : first (1, 0) then (1, 0) NOR : first (1, 0) then (1, 0)
(C) NAND : first (1, 0) then (1, 0) NOR : first (1, 0) then (0, 0)
(D) NAND : first (1, 0) then (1, 1) NOR : first (0, 1) then (0, 1)
Q-21) What are the counting states (, ) QQ 12for the counter shown in the figure below
(A) 11 10 00 11 10… (B) 01 10 11 00 01…
(C) 00 11 01 10 00… (D) 01 10 00 01 10…
ANSWERS:
1(C), 2(C), 3(C), 4(D) ,5(A), 6(B), 7(A), 8(D), 9(B), 10(A), 11(D), 12(A), 14(A,B,C), 15(B),
16(D),17(D),18(D), 19(A), 20(C), 21(A)
ELECTRONICS AND TELECOM ENGG DEPT
QUESTIONS ON EMFT & MW
1. A 50 ohm loss-less transmission line is terminated in 100 ohm load and is excited by a
30MHz source of internal resistance of 50 ohm. What should be the length of the
transmission line for maximum power transfer?
(a) 5.0m (b) 1.25m (c) 2.5m (d) 10.0m
2. The input impedance of a short-circuited loss-less line of length less than a quarter
wavelength is
(a) Purely resistive (b) Purely inductive (c) Purely capacitive (d) Complex
3. Which one of the following is the correct sequence of the frequency bands in order of
increasing available peak power?
(a) C-band, X-band, L-band, S-band
(b) X-band, C-band, S-band, L-band
(c) X-band, S-band C, -band ,L-band
(d) S-band, X-band, C-band, L-band
4. The skin depth at 1000 MHz, in comparison with that at 500 MHz is
(a) 2 (b) 2 (c) 1/ 2 (d)1/2
5. Which of the following statement is true, for EM wave propagation through a
rectangular waveguide of cross-section 2a x a?
(a) Critical wavelength for TE10 mode is the same as that for TE01 mode
(b) Critical wavelength for TE10 mode is half that for TE01 mode
(c) Critical wavelength for TE10 mode is the same as that for TM10 mode
(d) Critical wavelength for TE10 mode is double that for TE01 mode
6. In a rectangular waveguide there is one half-wave variation of electric field across the
narrow dimension and two half-wave variation of electric field across the wider
dimension. What is the dominant mode?
(a) TM12 (b) TE12
(c) TE21 (d) TM21
7. The intrinsic impedance of a medium with relative permittivity and relative
permeability of 4 and 1 respectively will be
(a) 75ohm (b) 377 ohm (c) 94 ohm (d)188ohm
8. Ionospheric propagation is not possible for microwaves because
(a) Microwaves will be fully absorbed by the ionospheric layers
(b) There will be an abrupt scattering in all directions
(c) Microwaves will penetrate through the ionospheric layers
(d) There will be dispersion of microwave energy
9. The degenerate modes in a waveguide are characterised by
(a) Same cut-off frequencies but different field-distributions
(b) Same cut-off frequencies and same field-distributions
(c) different cut-off frequencies but same field-distributions
(d) different cut-off frequencies and different field-distributions
10. Which of the following can be used for amplification of microwave energy?
(a) Travelling wave tube
(b) Magnetron
(c) Reflex Klystron
(d) Gunn diode
11. The skin depth of copper at a frequency of 3 GHz is 1 micron. At 12GHz for a nonmagnetic conductor whose conductivity is 1/9 times that of copper, the skin depth would be
a) 6 microns
b)
9
microns
4
c)
4
micron
9
d) 1/6 micron
12. The important postulate arising out of Maxwell’s modification of Ampere’s law is
a) a steady current produces a magnetic field
b) a changing magnetic field produces an electric field
c) a changing electric field produces a magnetic field
d) a motional emf is produced by a coil moving in a magnetic field
13. For distortionless transmission on a line
1. LC=RG
4.
𝑅
𝐺
=
2. vp should be constant
3. 𝛽/ω graph should be a straight line
𝐿
𝐶
Pick out the wrong statement
a) All four b) 1, 2, 3
c) 2, 3
d) 1
14. The power gain in dB of isotropic radiator is
a) 0
b) 1
c) 1.5
d) 1.64
15. If parabolic dish diameter increases
a) beam width becomes small , b) beam width becomes high, c) beam width becomes
high and sometimes small, d) beam width remains constant
16. In a travelling electromagnetic wave, E and H vector fields are
a) perpendicular in space .
b) parallel in space.
c) E is in the direction of wave travel.
d) H is in the direction of wave travel.
17. A wave is incident normally on a good conductor. If the frequency of a plane
electromagnetic
wave increases four times, the skin depth, will
a) increase by a factor of 2. b) decrease by a factor of 4.
c) remain the same. d) decrease by a factor of 2.
18. The lower cut-off frequency of a rectangular wave guide with inside dimensions (3 × 4.5
cm) operating at 10 GHz is
a) 10 GHz. b) 9 GHz. c) 10/9GHz. d) 10/3GHz.
19. In a dielectric-conductor boundary (interface), the tangential component of electric field
is (A) Et (B) 2Et (C) zero (D) infinity
20 . For a transmission line terminated in its characteristic impedance, which of the following
statement is incorrect:
(A) It is a smooth line.
(B) The energy distribution between magnetic and electric field is not equal.
(C) Standing wave does not exist.
(D) Efficiency of transmission of power is maximum.
Key:
1.(b) 2.(b) 3.(b) 4(c) 5(c) 6(c) 7(d) 8(c) 9(a) 10(a) 11. B , 12. C, 13. D, 14. A, 15.
A 16.C 17.D 18.D 19 C 20 B
MICRO-PROCESSOR:1. what is length of address bus of 80386
A.8 B.16 C.32
D.64
2.
2. Consider the following 8085 assembly program
MVI A, DATA1
MOV B, A
SUI 51H
JC DLT
MOV A, B
SUI 82H
JC DSPLY
DLT : XRA A
OUT PORT1
HLT
DSPLY : MOV A, B
OUT PORT2
HLT
This program will display
(A) the bytes from 51H to 82H at PORT2
(B) 00H AT PORT1
(C) all byte at PORT1
(D) the bytes from 52H to 81H at PORT 2
3. Consider the following 8085 assembly program :
MVI B, 89H
MOV A, B
MOV C, A
MVI D, 37H
OUT PORT1
HLT
The output at PORT1 is
(A) 89 (B) 37
(C) 00 (D) None of the above
4. Consider the sequence of 8085 instruction given
below
LXI H, 9258H
MOV A, M
CMA
MOV M, A
By this sequence of instruction the contents of
memory location
(A) 9258H are moved to the accumulator
(B) 9258H are compared with the contents of the
Accumulator
(C) 8529H are complemented and stored at location
529H
(D) 5829H are complemented and stored at location
85892H
5. 11. It is desired to multiply the number 0AH by 0BH
and store the result in the accumulator. The numbers
are available in register B and C respectively. A part of
the 8085 program for this purpose is given below :
MVI A, 00H
LOOP : ----------------------------------------------------------------------HLT
END
The sequence of instruction to complete the
program would be
(A) JNZ LOOP
ADD B
DCR C
(B) ADD B
JNZ LOOP
DCR C
(C) DCR C
JNZ LOOP
ADD B
(D) ADD B
DCR C
JNZ LOOP
616. The instruction, that does not clear the accumulator of 8085, is
(A) XRA A (B) ANI 00H
(C) MVI A, 00H(D) None of the above
7. Consider the following loop
XRA A
LXI B, 0007H
LOOP : DCX B
JNZ LOOP
This loop will be executed
(A) 1 times (B) 8 times
(C) 7 times (D) infinite times
8.Consider the following loop
LXI H, 000AH
LOOP : DCX B
MOV A, B
ORA C
JNZ LOOP
This loop will be executed
(A) 1 time (B) 10 times
(C) 11 times (D) infinite times
9..Consider the following program
MVI A, BYTE1
RRC
RRC
If BYTE1 32H, the contents of A after the execution of program will be
(A) 08H (B) 8CH
(C) 12H (D) None of the above
10... The contents of accumulator after the execution of following instruction will be
MVI A, A7H
ORA A
RLC
(A) CFH (B) 4FH
(C) 4EH (D) CEH
11.3. Consider the following set of instruction
MVI A, BYTE1
RLC
MOV B, A
RLC
RLC
ADD B
If BYTE1 = 07H, then content of A, after the
execution of program will be
(A) 46H (B) 70H
(C) 38H (D) 68H
12. The contents of some memory location of an 8085 P based system are shown
Address Hex. Contents (Hex.)
3000
02
3001
30
3002
00
3003
30
Fig. P4.6.17
The program is as follows
LHLD 3000H
MOV E, M
INX H
MOV D, M
LDAX D
MOV L, A
INX D
LDAX D
MOV H, A
The contents if HL pair after the execution of the program will be
(A) 0030 H (B) 3000 H
(C) 3002 H (D) 0230H
13. 13The contents of the accumulator after the execution
of the following program will be
MVI A, C5H
ORA A
RAL
(A) 45H (B) C5H
(C) C4H (D) None of the above
Statement for Q.14–15:
Consider the following program of 8085 assembly
language:
LXI H 4A02H
LDA 4A00H
MOV B, A
LDA 4A01H
CMP B
JZ FNSH
JC GRT
MOV M, A
JMP FNSH
MOV M, B
FNSH : HLT
14.
14. If the contents of memory location 4A00H, 4A01H
and 4A02H, are respectively A7H, 98H and 47H, then
after the execution of program contents of memory
location 4A02H will be respectively
(A) A7H (B) 98H
(C) 47H (D) None of the above
15. 15. The memory requirement for this program is
(A) 20 Byte (B) 21 Byte
(C) 23 Byte (D) 18 Byte
16. The instruction, that does not clear the accumulator
of 8085, is
(A) XRA A (B) ANI 00H
(C) MVI A, 00H (D) None of the above
17. Consider the following instruction to be executed by a 8085 p. The input port has an address of 01H and has a data
05H to input:
IN 01H
ANI 80H
After execution of the two instruction the contents of flag register are
(A) 1 0 ×1 ×1 ×0
(B) 0 1 ×0 ×1 ×0
(C) 0 1 ×1 ×1 ×0
(D) 0 1 ×1 ×0 ×0
18.The contents of accumulator after the execution of
following instructions will be
MVI A, B7H
ORA A
RAL
(A) 6EH (B) 6FH
(C) EEH (D) EFH
19. Consider the following program
MVI A, DATA
MVI B, 64H
MVI C, C8H
CMP B
JC RJCT
CMP C
JNC RJCT
OUT PORT1
HLT
RJCT : SUB A
OUT PORT1
HLT
If the following sequence of byte is loaded in accumulator,
DATA (H) 58 64 73 B4 C8 FA
then sequence of output will be
(A) 00, 00, 73, B4, 00, FA
(B) 58, 64, 00, 00, C8, FA
(C) 58, 00, 00, 00, C8, FA
(D) 00, 64, 73, B4, 00, FA
20. In an 8085 microprocessor, the instruction CMP B has been executed while the contents of accumulator is less
than that of register B. As a result carry flag and zero flag will be respectively
(A) set, reset (B) reset, set
(C) reset, reset (D) set, set
ANSWER:1.C 2.D 3.A 4.D 5.D 6.D 7.A 8.B 9.B 10.B 11.A 12.C 13. A 14.A 15.C 16.D 17.C 18. A 19.D 20.A
ELECTRONICS AND TELECOM ENGG DEPT
QUESTIONS ON AEC,NAS,VLSI
1.
a)
b)
2.
a)
b)
3.
a)
b)
4.
a)
b)
Which of the following components are not fabricated in an integrated circuit?
Resistor, capacitor
c) Capacitor ,transistor
Inductor
d) None of these
Operating point means
Zero signal IE and VCE
c) Zero signal IC and VCE
Zero signal IC and VBE
d) Zero signal IB and VCE
The output impedance of an ideal OPAMP is
infinite
c) zero
very high
d) very small
When transistor is operating in saturation region
Collector junction is forward biased
c)Collector junction is reverse biased
Both collector and emitter junction are forward biased
d) Both collector and emitter junction are
reverse biased
5. In an RC coupled amplifier the voltage gain
a) remains almost constant over a range of frequency
c)always increases with frequency
b)
6.
a)
b)
7.
a)
always decreases with frequency
The
More than unity
Between 0.95 and 0.99
A practical current source is usually represented by
A resistance in series with an ideal current source
current source.
b) A resistance in parallel with an ideal voltage source.
voltage source
d) none of the above
c) Unity
d) Negative
c) A resistance in parallel with an ideal
d) A resistance in series with an ideal
8. In a practical voltage source, the terminal voltage
(a) cannot be less than source voltage
(b) cannot be higher than source voltage
(c) is always less than source voltage
(d) is always equal to source voltage
9. In a purely capacitive circuit, the current …………the voltage by ……. ……
(a) lags, 00
(b) leads, 900
(c) lags, 900
(d) lags, 450
10. A bulb rated at 60W, 120V is used for 30 minutes. The charge associated with this operation is
(a) 3600 C
(b) 60C
(c) 7200 C
(d) 900 C
11. Two capacitors of 1 μF and 2 μF are connected in series across a 30 V dc battery. After the capacitors
have been charged, the charges across the two capacitors will be
(a) 10 μC each
(b) 20 μC each
(c) 10 μC and 20 μC
(d) 20 μC and 10 μC
12. The Voltage V in Figure is equal to
(a) 3 V
(b) -3 V
(c) 5 V
(d) None of these
13. The average power delivered to an impedance (4 – j3)Ω by a current 5 cos (100πt + 100) A is
(a) 125 W
(b) 62.5 W
(c) 50 W
(d) 44.2 W
14. The short-circuit admittance matrix of a two-port network is
(a) non – reciprocal and passive
(b) non – reciprocal and active
(c) reciprocal and passive
(d) reciprocal and active
 0 1/2 
1  2
0 

15. Standard cell based design takes ------- time as FPGA based design.
b) Less
a) More
c) Equal
d) Same
16. The phenomenon in MOSFET like early effect in BJT is -------.
a) Body effect
b) Hot carrier effect
. The two – port network is
c) Channel length modulation
d) Subthreshold condition
17. In full scaling the power dissipation is ------a) Decreased by a factor S
b) Increased by a factor S2
c) Remain unchanged
d) Increased by a factor S3
18. A hard macro refers to a ------a) Flexible block
b) Flexible block with fixed aspect ratio
c) Fixed block
d) Flexible block with fixed pin locations
19. Which of the following has minimum propagation delay?
a) ECL
b) TTL
c) RTL
d) DTL
20. In VHDL sequential statements are defined in the ------a) Entity
b) Architecture
c) Package
d) Process
21. In VLSI Logic Design process we can -----a) Minimize both area and delay
b) Minimize area at the cost of delay
c) Maximize speed by decreasing area
Answers:
1. (b)
2. (c)
3. (c)
4. (b)
5. (a)
6. (b)
7. (c)
8. (b)
9. (b)
10. (d)
11. (b)
12. (a)
13. (c)
14. (b)
15. (a)
16. (c)
17. (b)
18. (c)
19. (a) 20. d, 21. b
d) Minimize delay by reducing area