| Post Name | ASSISTANT PROFESSOR ELECTRONICS AMD COMMUNICATION ENGG. - TECH. EDN. |
|---|---|
| Question Paper Code | 051/2023 |
| Category Code | 725/2021 |
| Date of Test | 18 June 2023 |
| Medium of Question | ENGLISH |
| Exam Type | OMR Examination |
| Total Questions | 100 |
1
For the circuit shown in the figure, the Thevenin equivalent resistance (in Ω) across
P-Q is
–+
3i0
P
1Ω i0
+
10 V – 1Ω 1Ω
1Ω
Q
Answer
A. – 1
2
In the circuit shown what value of Rl minimizes the power delivered to Rl ?
Vx 4Ω
–+
4Ω 4Ω
–V +
+ x
100 V – Rl
8
Answer
Question Cancelled
3
Polysilicon and thinox regions interact so that a transistor is formed where they
cross one another.
Which of the above statements are correct ?
Answer
D. 1, 2 and 3
4
In the figure, the switch was closed for a long time before opening at t = 0. The voltage
Vx at t = 0+ is
t=0
20Ω 2.5A
5H
– 20Ω +
Vx
Answer
B. – 50 V
5
For the circuit shown in figure, the value of v0(t) (in volts) for t → ∞ is
ix 2H
2 ix +
– +
10u(t)A 5Ω v0(t)
5Ω –
Answer
A. 31.25
6
If capacitor is energized by symmetrical square wave current source, then the
steady-state voltage across the capacitor will be a
Answer
C. Triangular wave
7
In a linear circuit the superposition principle can be applied to calculate the
Answer
A. Voltage and Current
8
The poles and zeros of a driving-point function of a network are simple and interlace
on the negative real axis with a pole closed to the origin. It can be realized
Answer
B. As an RC driving-point impedance
9
In a non-degenerate bulk semiconductor with electron density n = 1016 cm–3, the
value of Ec – EFn = 200meV. Assume the thermal voltage is 26 meV and the intrinsic
carrier concentration is 1010 cm–3. For n = 0.5 × 1016 cm–3, the closest approximation
of the value (Ec – EFn) is
Answer
C. 218 meV
10
drift current in semiconductors depends upon
Answer
C. Both the electric field and carrier concentration
11
Consider the following statements regarding MOS circuit design process.
1. MOS circuits are formed on four basic layers n-diffusion, p-diffusion, polysilicon
and metal; which are isolated from one another by thick or thin silicon dioxide
insulating layers.
2. Thin oxide (Thinox) mask region includes n-diffusion and p-diffusion and
transistor channel.
3. Polysilicon and thinox regions interact so that a transistor is formed where they
cross one another.
Which of the above statements are correct ?
Answer
C. 2 and 3 only
12
Consider the nmOS transistor in a 65 nm process with a nominal threshold voltage
of 0.3 V and a doping level of 8 × 1017 cm–3. The body is tied to the ground with a
substrate contact. How much does the threshold change at room temperature if the
source is at 0.6 V instead of 0 ?
Answer
Question Cancelled
13
For an n-channel enhancement type mOSFET, if the source is connected at a higher
potential than that of the bulk (i.e., VSB > 0), the threshold voltage VT of the mOSFET
will
Answer
D. Increase
14
What is the minimum threshold voltage for which the leakage current through an
OFF transistor (Vgs = 0) is 103 times less than that of a transistor that is barely ON
(Vgs = Vt) at room temperature if n = 1.5 ?
Answer
B. 270 mV
15
In CmOS inverter if Vtn ≤ Vin < Vdd/2 then the following is behaviour of the inverter
Answer
A. p-mOS linear, n-mOS saturated
16
The difficulty in achieving high doping concentration leads to
Answer
B. Error in variation
17
The advantage of NORA CmOS logic is that
Answer
A. A static CmOS inverter is not required at the output of every dynamic logic
stage. Instead, direct coupling of logic blocks is feasible by alternating nmOS
and pmOS logic blocks.
18
Consider a process with a subthreshold slope of 100 mV/decade and a dIBl
coefficient of 0.15. How far must the power supply droop to cut subthreshold leakage
by a factor of 2 ?
Answer
D. 200 mV
19
A CE amplifier has a resistor RF connected between collector and base, RF = 40k
RC = 4k. If hfe = 50, rϖ = 1k, then output resistance RO is
Answer
Question Cancelled
20
An amplifier has a open loop gain of 100, an input impedance of 1kΩ, and an output
impedance of 100Ω. If a feedback network with a feedback factor of 0.99 is connected
in voltage series feedback mode, then new input and output impedance are
Answer
C. 100kΩ and 1Ω
21
If a differential amplifier has a differential gain of 20000. CMRR = 80dB, then common
mode gain is
Answer
A. 2
22
An Op-Amp has a slew rate of 5V/µs. The largest sine wave output voltage possible
at a frequency of 1mHz is
5 5
Answer
D. volts
π 2π
23
A 10-bit A/d converter is used to digitize an analog signal in the 0V to 5V range. The
maximum peak to peak ripple voltage that can be allowed in the d.c supply voltage is
Answer
D. Nearly 5 mV
24
An analog voltage is in the range of 0 to 8V, is divided in eight intervals for conversion
to 3-bit digital output. The maximum quantization error is
10V
Id
Rd
Answer
B. 0.5V
25
For the n-channel enhancement MOSFET shown in the given figure, threshold voltage
Vth = 2V. The Drain current Id of the mOSFET is 4mA when the drain resistance Rd
is 1KΩ. If the Rd is increased to 4KΩ, then the drain current Id will become
Answer
Question Cancelled
26
An astable multivibrator circuit using IC 555 timer is shown below. Assume that the
circuit is oscillating steadily. The voltage VC across the capacitor varies between
30 K 9V
4 8
(Reset) (Supply)
6 (Threshold)
10 K
Answer
B. 3V to 6V
27
The steps involved in the FPGA implementation process are mapping, Translate,
Place and Route. Arrange these implementation steps in the sequence they are
performed.
Answer
C. Translate, mapping, Place and Route
28
The Boolean expression y(A, B,
Answer
B. 3
29
Find the complement of the expression y(A, B, C) = ABC + ABC + A BC + ABC
A)
Answer
D. + C)
C) (A + B) (A + C) D) (A + B) (A + C)
30
Measuring units of the figure of merit
Answer
C. Pico joules
31
The number of distinct Boolean expressions of 3 variables
Answer
B. 256
32
A certain JK FF has tpd = 10 ns. The largest MOD counter that can be constructed
from such FFs and still operate up to 20 mHz is
Answer
A. 32
33
Among the digital IC-families, which of the following statements are false ?
i. ECl is a non-saturated logic family.
ii. HTl has the biggest noise margin.
iii. CmOS has the Highest fanout.
Answer
D. None
34
The minimal function that can detect a “divisible by 4” 8421 BCd code digit
(representation is D3d2d1d0) is given by
Answer
A. F = d1d0
35
Thumb technology in ARm processor is used to
Answer
A. create variable length instruction set
36
Bit 7 of CPSR of ARm processor is
Answer
C. Interrupt disable bit
37
dispatch latency is
Answer
B. the time interval between termination of one task and starting of another task
38
A CISC is not characterized with
Answer
C. more general-purpose registers
39
How is baud rate modified in 8051 ?
Answer
B. Using mSB of PCON register
40
Cycle stealing is used to
Answer
A. Accessing computer memory/bus
41
memory space from 80H to F8H in 8051 processor are reserved for
Answer
C. SFR
42
Given X_e(t) = (1/2)[x(t) + x(−t)] is the even signal component of
Answer
Question Cancelled
43
Given signal x(t) = e–2t cos (2πt) is
Answer
C. Non Periodic
44
The fundamental period of the given sinusoidal signal x[n] = 10 cos((4πn/31) + (π/5)) is
Answer
D. 31 samples
45
The Fourier representation of x(t) = e–t cos (2πt) u (t)
Answer
D. FT
46
The impulse response of a LTI system is h(n) = (1/2)nu[n]. The output of this system
is ____________ when the input given is x[n] = 2(–1/2)nu[n].
Answer
A. y[n] = (1/2)nu[n] + (–1/2)nu[n]
47
The forced response of the given system described by y[n] + 3y[n – 1] = x[n] + x[n – 1] is
Answer
Question Cancelled
48
____________ pulse plays a key role in digital communication.
Answer
Question Cancelled
49
The approach used in the design of analog and digital filters
Answer
Question Cancelled
50
For the given transfer function of band pass filter 0.1s/(s2 + 0.1s + 1), the mid-band
frequency and bandwidth are
Answer
C. 1 & 0.1
51
1. Unfiltered speech signal is harsh.
2. Filtered speech signal is soft.
Answer
Question Cancelled
52
The magnitude of vector
Answer
Question Cancelled
53
Given Vector A = (–3ar + 2aθ + 1a∅) is _________ to Vector B = (5ar + 6aθ + 3a∅).
Answer
C. Perpendicular
54
___________ is defined as the total flux out of a closed surface is equal to the net
charge within the surface.
Answer
B. Gauss’s law
55
The Electric field E is ____________ to the electric equipotential lines.
Answer
B. Normal
56
The insertion of displacement current in Ampere’s law is basically done to
Answer
A. Satisfy equation of continuity
57
lenz’s law is applicable for
Answer
A. Closed loop
58
When an equivalent T – network in a equivalent circuit of a transmission line is
replaced by equivalent π – network
Answer
C. The telegrapher line equation remains same
59
The propagation of electromagnetic wave is in (–Z) direction, if electric field component
is along ____________ and magnetic field component is along __________
direction.
Answer
A. y & X
60
An inductance of 0.1 nH at 10 GHz represents a reactance of
Answer
A. 6.28 ohms
61
A capacitance of 0.1 pF at 10 GHz has a reactance of
Answer
D. 159 ohms
62
In a transmission line, __________ is the attenuation due the conductor loss for the
given R1 and R2 and Zc.
Answer
Question Cancelled
63
Bethe-hole coupler consists of __________ rectangular waveguides.
Answer
C. 2
64
What is the coherence bandwidth when a radio channel is characterized by 4
millisecond multipath spread ?
Answer
C. 250 Hz
65
For the given coherence time of 100 sec, the doppler Spread is equal to
Answer
A. 0.01 Hz
66
IEEE 802.11 wireless technology employ __________ multiple access scheme to
avoid collision.
Answer
D. CSmA/CA
67
In WlAN, the channel bandwidth is divided into ______ sub channels with subcarrier
frequency spacing of 312.5 KHz.
Answer
B. 52
68
In a dSSS communication system, the processing gain in dB for the given
(SNR)d = 20 and PI/PS = 100 is
Answer
Question Cancelled
69
The differential entropy of a random variable X when uniformly distributed in
Answer
C. log a
70
The difference between the true value and the measured value of the quantity
Answer
A. Static error
71
A Wheatstone bridge is constructed with two strain gauge and two resistors. One
strain gauge is active and other one is dummy. These two are in the opposite arms
of a Wheatstone bridge. The other two arms are formed with resistors of equal
resistance of 120 ohms each at 300 K. The frequency bandwidth is 100,000 Hz.
When a pressure of 7000 kN/m2 is applied, and the output voltage is 0.12 mV. Find
signal to noise ratio generated by the resistors.
Answer
A. 269
72
Two resistors R1 = 29.5 ohms and R2 = 69 ohms are connected in series. Then the
total resistance is
Answer
D. 98.5
73
In Photoconductive transducer
Answer
A. Change in conductivity appears as change in resistance
74
Time required by a measurement system to begin to respond to a change in the
measurand is
Answer
D. dead time
75
In a pyrometer, the dead zone is assumed to be 0.125 percent of span. Calibration
can be done from 400°C to 1000°C. determine the change in temperature expected
before the occurrence can be detected.
Answer
C. 0.75°C
76
Assume a voltmeter
Answer
A. 1.5
77
Construct a parallel circuit with two branches. The current in one branch is I1 = 200 ± 7A
and in the other is I2 = 200 ± 1A. Then the value of total current considering the errors
in I1 and I2 as limiting errors is
Answer
D. 400 ± 8A
78
The steady state error of a control system with unity feedback and transfer
function
C(s) 1
= 2
R(s) s + s + 1
when exited with a unit ramp input is,
Answer
B. ess = 1
79
Consider the first order system with a closed loop transfer function
1
Ts + 1
dc
What is the slope of unit step response at t = T, where c(t) is the unit step response
of the system ? dt
dc 1
Answer
B. =
dt e dt eT
dc e dc
80
In the bridge T network shown in figure, Z1 = Z3 = R and Z2 = Z4 = . If RC = τ,
Cs
the overall transfer function of the network is given by
Z4
Z1 Z3
In Z2 Out
τ2 s2 + 3τs + 1 2τ2 s2 + τs + 1
Answer
D. H(s) = 2 2
2τ s + τs + 1 τ s + 3τs + 1
81
Considering the Hurwitz condition for stability, choose the most accurate statement
for the system with characteristic equation s4 + 2s3 + (4 + K)s2 + 9s + 25 = 0.
Answer
C. The system is stable when K > 7
82
Consider the root loci of the system with
K
G(s) =
s(s + 1) (s + 2)
and H(s) = 1. The number of asymptotes and the point of intersection are
Answer
D. Three asymptotes meets at s = – 1
83
The forward transfer function of a unity feedback system is given by
1+ s
G(s) =
1 + 2s + 3s 2
The number and direction of encirclements around the point –1 + j0 in the complex
plane by the Nyquist plot is
Answer
A. Zero
84
The state space representation of a system is given by ẋ = Ax + Bu and y = Cx, where A = [[0, 1], [−2, −3]], B = [[0], [1]], C = [3, 1]. The system is represented by
Answer
A. Y(s)/U(s) = (s + 3)/(s² + 3s + 2)
85
Consider the compensation network given by
1
s+
T1
G(s) =
1
s+
T2
determine the condition for network to be a lead network.
Answer
C. If T1 > T2 it is a lead network
86
The state space representation of a system is given by ẋ = Ax + Bu and y = Cx, where A = [[1, 1], [−2, −1]], B = [[0], [1]], C = [1, 0]. Choose the correct statement.
Answer
D. The system is completely controllable and completely observable.
87
A proportional controller with unity feedback has a forward transfer function G(s) = 1/(Ts + 1). The steady state error for unit step input is
Answer
B. 1/2
88
Consider the statements. 1 :- A super-lattice is a periodic structure of layers of two
Answer
C. Statements 1 is correct but 2 is false
89
Consider the two statements given below.
1 :- Quantum well is a two dimensional nano structure in which there is a confinement
in one dimension and particle is free to move in the other two dimensions.
2 :- Quantum dot is a one dimensional nano structure in which there is confinement in
two dimensions and particle is free to move in the third dimension only.
Answer
C. Statement 1 is correct and 2 is wrong
90
In the ISO OSI seven layer model, the raw bits are converted to frames by
Answer
B. data link layer
91
An IPv4 datagram has type of service (TOS) bits ‘1000’. The datagram service type is
Answer
B. minimize delay
92
A discrete source emits five symbols independently with frequencies as given
below.
Answer
Question Cancelled
93
A (7,4) linear block code is generated by the matrix G = [[1,0,0,0,1,1,1], [0,1,0,0,1,1,0], [0,0,1,0,1,0,1], [0,0,0,1,0,1,1]]. If a received code vector R is affected by an error vector E = [0,0,1,0,0,0,0], the syndrome of R will be
Answer
A. 101
94
The following figure shows various DC to DC converter configurations. Starting from
top to bottom, the configurations are,
Answer
C. Buck, Boost, Buck-boost and Cuk
95
In a DC motor control circuit as shown in figure, by using PWM and /or logic signals
at the input points,
VCC 1
T
Input
mOTOR
Input
Answer
A. The speed and direction of rotation of the motor can be controlled
96
An image segment of size 6 × 6 is convolved with a mask [– 1 2 – 1]T. Assume
replication at the edges.
1 1 1 1 1 1
1
1 1 1 1 1
1 1 1 1 1 1
f(x, y) =
0 0 0 0 0 0
1 1 1 1 1 1
1 1 1 1 1 1
Number of non zero values in the resulting image will be,
Answer
C. 18
97
A simplified stereo camera model is given in figure. The equations for x and z in
P(x, z), with respect to camera L is given by,
Image planes
z
f
Camera l Z
xl
baseline b
f
Camera R xr
x–b
X P = (x, z)
f ×b xr × z
Answer
D. z = and x =
xl − xr f
98
Consider the following statements about micro electro mechanical systems.
1. Surface to volume ratio of MEMS are higher than the macro scale systems.
2. Electrostatic forces dominate over gravitational forces at micro scale.
Answer
A. Both the statements 1 and 2 are true
99
Consider the linear programming problem to minimize z = 5x + 4y subject to
4x + y ≥ 10, 2x + 3y ≥ 10 and x, y ≥ 0. minimum value of z is
Answer
B. 18
100
Consider the following statements.
1. Message Queuing Telemetry Transport (MQTT) and Constrained Application
Protocol
2. MQTT uses a Publish/subscribe communication model and it is a many-to-
many communication protocol.
Answer
D. Both the statements 1 and 2 are correct
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