| Post Name | ASSISTANT ENGINEER (ELECTRONICS) (PUBLIC WORKS DEPARTMENT) |
|---|---|
| Question Paper Code | 094/2025 |
| Category Code | 071/2024 |
| Date of Test | 29 July 2025 |
| Medium of Question | ENGLISH |
| Exam Type | OMR Examination |
| Total Questions | 100 |
1
The colour code of 2.7K resistor with the tolerance value of ± 5% is :
Answer
C. Red Violet Red Gold
2
The knee voltages of silicon and germanium diodes are respectively :
Answer
D. 0.7 V and 0.3 V
3
The material used for the blue colour LED is :
Answer
A. InGaN
4
The β of a transistor
Answer
B. JT) is 99. When the emitter current is 5mA, the collector current
will be:
5
Which one is the best true statement in case of semiconductor diode breakdown
mechanisms?
Answer
D. Both are true statements
6
In the cutoff region of a bipolar junction transistor :
Answer
Question Cancelled
7
Which among the below is a wrong statement in the case of a MOSFET?
Answer
D. MOSFET channel is the region between the gate and drain where current
flows
8
The channel-length modulation parameter lambda, λ in the drain current (ID) equation
for a MOSFET in saturation is
Answer
B. process dependent parameter
9
From the equivalent circuit of the two transistor model of an SCR, if the common-base
current gains are α1 and α 2 , then theoretically the anode current Ia becomes infinity
under the condition :
Answer
C. α1 + α 2 = 1
10
Which one is the best true statement in the power electronics?
Answer
D. Both are true statements
11
Find the current I in the circuit. An ideal op-amp is powered by a dual supply of ±15 V. The non-inverting input is connected to +5 V; the output drives R_L = 1 kΩ in series with R_s = 2 kΩ to ground, and the inverting input senses their junction.
Answer
B. 2.5 mA
12
An ideal op-amp is powered by a dual supply of ± 15 V . Compute the current I1 through
the resistor R1.
Answer
C. –6 mA
13
For the circuit shown in the figure, the time period of the generated square wave is given
by
Answer
C. 2RC ln 7
14
A practical op-amp is configured as an inverting amplifier with a gain of 100. The
maximum frequency at which an undistorted output can be obtained is 10 KHz. If the
op-amp has a slew rate of 0.25 V/ μ s, what is the maximum peak voltage of the
sinusoidal input signal that can be applied without causing output distortion?
Answer
A. 0.0398 V
15
In the circuit shown, an input signal Vi is applied as indicated. Which of the following
best describes the output Vo obtained from the circuit?
Answer
A. –2C – 0.002t
16
In the illustrated ideal-diode circuit, a sinusoidal input V_i with peaks of +30 V and −30 V is applied across the network. The right branch is a pair of 5 kΩ resistors; the left branch contains the opposing diodes D2 and D1, and the two midpoints are connected through 5 kΩ. V_o is measured from the right midpoint (+) to the left midpoint (−). Which waveform best represents V_o?
Answer
B. A full-wave rectified positive waveform with peaks at +10 V
17
A PLL 565 circuit is observed to have a free-running frequency of 3 kHz. If the timing
capacitor used is 0.01 μ F, what is the approximate value of the external resistor?
Answer
A. 10 kΩ
18
A 555 timer circuit is wired as shown, with an output taken from pin number 3. The
component values are : R1 = 10 kΩ , R2 = 20 kΩ and C = 0.1 μ F. What is the duty cycle
(%) of the output waveform?
Answer
D. 60%
19
A Hartley oscillator circuit uses a frequency-determining network consisting of a 100 pF
capacitor and two identical 10 μ H inductors.
The circuit satisfies the Barkhausen criterion for sustained oscillations.
If the inductors are replaced with 1 μ H inductors, what happens to the oscillation
frequency?
Answer
B. Increases by a factor of 10
20
A system employs of a four-stage cascade amplifier, where each stage is designed with a
lower 3 dB cutoff frequency of 40 Hz and an upper 3 dB cutoff frequency of 2 MHz.
Assuming all stages are identical and cascaded without additional filtering or feedback,
what is the effective 3 dB bandwidth of the complete amplifier chain?
Answer
D. 91.96 Hz to 869.96 kHz
A 7 094/2025
21
The largest positive and negative values that can be expressed in 2’s complement
notation with n bits are, respectively :
Answer
D. + (2n −1 −1), − 2n −1
22
Conversion of the excess-3 code to BCD is not possible using :
Answer
B. A 4 bit half adder
23
The Sum of Products (SOP) format for logical expressions is particularly well-suited for
the design of logic circuits that utilize only :
Answer
C. NAND gates
24
According to De Morgan’s theorem, the NOR gate is equivalent to :
Answer
A. Bubbled AND
25
Consider the following 4-variable Boolean function expressed in SOP form
F
Answer
B. 1
26
A 16:1 multiplexer is constructed using 5:1 multiplexers (each 5:1 MUX has 5 data
inputs, 3 select lines, and 1 Output). What is the minimum number of 5:1 multiplexers
required to build this 16:1 MUX? :
Answer
C. 5
27
A positive edge-triggered D flip-flop has D = 1 (constant) and the CLK waveform shown in the official source. Assume the flip-flop is initially reset (Q = 0). What will be the output Q after 3 clock edges?
Answer
B. 1
28
A 4-bit Johnson counter starts at 0000. After receiving 6 clock pulses, what will the
output state of the counter be?
Answer
A. 0011
29
TTL circuits featuring active pull-up configurations are favored due to their
appropriateness for:
Answer
D. Reasonable dissipation and speed of operation
30
Which of the following does not represent a characteristic of CMOS configuration?
Answer
C. CMOS devices have low input impedance
31
With respect to a microprocessor which one of the following is FALSE?
Answer
B. A machine cycle comprises of several instruction cycles
32
Cache memory in a microprocessor is
Answer
B. Static memory
33
The addressing mode of MOV A, B instruction in a microprocessor is :
Answer
A. Register addressing since A and B are registers
34
DMA in a microprocessor based system refers to :
Answer
C. Direct Memory Access
35
Which of the following statements is TRUE?
Answer
A. DRAMS are used as primary memory
36
Stack Pointer in a microprocessor points at :
Answer
C. Last filled location of a stack
37
In a CISC processor, the number of machine cycles in an instruction fetch will :
Answer
D. Depend on the type of instruction
38
SHIFT and ADD algorithm can be used for :
Answer
D. Binary Multiplication
39
In a 4 kilobyte memory chip, the number of address lines needed are :
Answer
C. 12
40
CISC processors have :
Answer
D. Variable instruction size and variable data size
41
If an impulse signal is delayed by 5 unit of time and added with the original impulse
signal the resultant signal is?
Answer
C. δ (t ) + δ (t − 5 )
42
Impulse response of a system is given by h(t) = e⁻ᵗu(t). The system is:
Answer
A. Stable
43
A signal is given by the equation f (t ) = 10 sin 50t + 2 sin100t + 0.2 sin 200t . The
fundamental frequency of the signal is ––––––––––– rad/sec.
Answer
B. 50
44
Condition for periodicity of a continuous time signal is :
Answer
A. x (t ) = x (t + T0 )
45
The output of a system is y(t ) = x (t ) + x (t −1) the system is :
Answer
B. Linear time invariant
46
Laplace transform of t 2u(t ) is :
Answer
B. 2
S3
47
A function which has the same Fourier transform and Laplace transform is :
Answer
D. Unit impulse function
48
Fourier transform of the signal x(t) = e⁻ᵃᵗu(t) is given by:
Answer
B. 1/(a + jω)
49
The difference equation y(n ) = x (n ) + 3x (n −1) − x (n − 7) represents :
Answer
C. An FIR filter
50
Z transform of a function x(n) = nu(n) is given by:
Answer
D. z/(z − 1)², ROC (|z| > 1)
51
What is the most appropriate coordinate system to use for analyzing a point charge
placed at the origin?
Answer
C. Spherical
52
Biot-Savart’s Law is used to calculate which of the following?
Answer
B. Magnetic field intensity due to a current distribution
53
Ampere’s Circuital Law relates the line integral of the magnetic field intensity around a
closed loop to the :
Answer
B. Total current enclosed by the loop
54
The phenomenon where an electromagnetic wave’s amplitude decreases as it propagates
through a lossy medium is characterized by the :
Answer
A. Attenuation constant
55
Which physical concept is best described by the curl of a vector field?
Answer
D. The rotational tendency or circulation of the field
56
The electric potential gradient is equal to which of the following?
Answer
A. Negative of the electric field intensity
57
What happens to the phase velocity of a uniform plane wave in a good conductor as the
frequency increases?
Answer
C. Increases with increasing frequency
58
What does a Standing Wave Ratio (SWR) of 1 indicate on a transmission line?
Answer
D. Perfect impedance matching
094/2025 14 A
59
For a uniform plane wave propagating in free space, the ratio of the magnitudes of the
electric field intensity to the magnetic field intensity (|E|/|H|) is equal to :
Answer
B. The intrinsic impedance of free space
60
Poynting’s Theorem relates the rate of change of electromagnetic energy density to :
Answer
A. The power flow and ohmic losses
61
The noise temperature of a receiver working at room temperature of 27°C with a noise
figure 1.02 is :
Answer
C. 6K
62
Which of the following statements is/are true in Amplitude Modulation
Answer
B. Only (iii) and (iv)
63
A message signal m(t) = sin 1000πt + sin 5000πt modulates a carrier of frequency 5 MHz to produce AM. For demodulating it using an envelope detector, the RC time constant should satisfy:
Answer
A. 0.2 μs << RC << 0.4 ms
64
For an FM modulator with frequency deviation 50 kHz and modulating signal frequency
of 10 kHz, the approximate bandwidth is :
Answer
D. 120 kHz
65
A superheterodyne receiver is tuned to receive an AM signal of 800 kHz avoiding image
frequency. Which among the following can be the local oscillator frequency and image
frequency respectively of the receiver? (Take IF = 455 kHz)
Answer
B. 1255 kHz, 1710 kHz
66
A video signal band limited to 5 MHz is transmitted through the channel by using 8-bit
PCM. What is the data rate in bits/s if the signal is sampled at least 20% higher than the
Nyquist rate?
Answer
D. 96 × 106 bits/s
67
Which among the following for Delta modulation is false?
(i) It is a 1 bit DPCM
(ii) It uses a two level quantizer
(iii) It is preferred for highly correlated input signals
(iv) The bandwidth required is lower than that of PCM and DPCM.
Answer
D. None of these
68
Which is NOT the property of manchester code?
Answer
B. It avoids channel inversion problem
69
Identify the digital modulation scheme with the following signal constellation :
Answer
A. BPSK
70
For a Hamming code with 10 parity bits, what are the total bits and data bits possible in
a codeword?
Answer
C. (1023, 1013)
71
During a live recording session in a state-of-the-art studio, a premium condenser
microphone exhibits a narrow dip in its frequency response around 8 kHz. After
confirming that the preamplifier is functioning correctly and that both the diaphragm
and backplate are undamaged, which of the following is the most likely cause of the
observed issue?
Answer
D. A resonance anomaly within the microphone’s internal acoustic impedance
network
72
A thermistor RT varies from 10 kΩ at 25°C to 5 kΩ at 50°C. Calculate its sensitivity :
Answer
C. –200 Ω/°C
73
A Venturi-meter is used to measure the flow rate of water in a pipe. The diameter of the
pipe is 0.4 m and the diameter of the throat is 0.2 m. If the pressure difference is
8000 Pa, what is the ratio of the fluid velocity in the pipe to the fluid velocity in the
throat? Assume ideal flow conditions :
Answer
B. 0.25
74
Which of the following velocity sensors offers a non-contact method for measuring
rotational speed? This option is especially effective for very high RPMs, where physical
contact is either undesirable or impractical?
Answer
C. Stroboscope
75
Which of the following is the principle behind the operation of an electromagnetic flow
meter?
Answer
B. Faraday’s Law
76
In optical range sensors, the main limitation of structured light (2D) systems compared
to laser range finders is :
Answer
C. Susceptibility to variations in ambient lighting
77
A CCD camera sensor offers benefits compared to a CMOS camera primarily in :
Answer
A. Higher dynamic range and uniformity
78
In a capacitive displacement sensor, if the separation between the plates is halved while
the dielectric constant is increased two fold, the capacitance will :
Answer
C. Quadruple
79
Which factors are responsible for hysteresis error in a resistive strain gauge
measurement system?
Answer
B. Residual mechanical strain after unloading
80
In a Public Address (PA) system, feedback noise is mainly generated by :
Answer
D. Over-amplification of the audio signal
81
A Doppler radar sensor operating at 10 GHz detects a frequency shift of 333 Hz. What is the relative speed of the target object (assume speed of light = 3 × 10⁸ m/s)?
Answer
A. 5 m/s
82
In an inductive proximity sensor, the detection distance increases with :
Answer
B. Higher excitation frequency
83
A sound intensity of 10–6 W/m2 is recorded. What is the sound level?
Answer
A. 60 dB
84
An accelerometer has a natural frequency of 500 Hz. For accurate dynamic
measurement, what should be the minimum frequency of the signal to be measured to
avoid resonance and ensure linearity?
Answer
B. 50 Hz
85
Two sensors A and B have time constants of 2 ms and 5 ms respectively. If both are
subjected to a step input simultaneously, which sensor reaches 63.2% of its final value
faster and by how much time difference?
Answer
A. Sensor A, 3 ms faster
86
The main component in a Hall-effect sensor responds to :
Answer
B. Magnetic field
87
Which of the options listed is not considered a dynamic characteristic of a sensor?
Answer
C. Accuracy
88
The main limitation of using a U-tube manometer for rapid pressure transients is :
Answer
B. Poor dynamic response
89
In a torque sensor that utilizes a resistive strain gauge, why a Wheatstone bridge is
favoured instead of a simple voltage divider?
Answer
C. It eliminates temperature effects and improves linearity
90
A measurement system uses a transducer that generates its own voltage output in direct
proportion to the rate of change of a magnetic field. This transducer, which does not
require an external power source for its operation, is best classified as :
Answer
B. An active, primary and analog transducer
91
Assertion
Answer
A. : The skin effect is much smaller with stranded conductors than with
solid conductors.
Reason [R] : Skin effect depends upon the type of material and supply frequency.
92
How does the rise in voltage at the receiving end of an open-circuited line depend on the
length of the line and the system operating voltage?
Answer
C. Proportional to the square of the length of the line and
varies directly in proportion to the system operating voltage
93
The sag of a transmission line is least affected owing to :
Answer
A. Current through the conductor
94
Assertion
Answer
C. [A] is true, [R] is false
95
The quality of a protective relay, by which it can discriminate between a fault in the
protected section and the normal condition, is termed :
Answer
B. Selectivity
96
Match the items given in List 1 and those in List 2 :
List 1 List 2
Answer
D. Buchholz relay (4) Transmission line
97
A 10 MVA, 12 kV alternator has positive, negative and zero sequence reactances of 10%,
20% and 5% respectively. The value of base impedance for fault current limiting
resistance computation is :
Answer
C. 14.4 Ω
98
A 4-pole, 50 Hz turbo alternator has an inertia of 10,000 kg-m2. The kinetic energy
stored in the rotor at synchronous speed is :
Answer
D. 492.98 MJ
99
Which of the following statements regarding the Gauss-Seidel load flow method is
incorrect?
Answer
B. Convergence characteristics of the Gauss-Siedel method are not affected by
the selection of the slack bus
100
Assertion
Answer
B. Both
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