| Post Name | Assistant Engineer (Electrical) 123/2023,505/2023 |
|---|---|
| Question Paper Code | 089/2024 |
| Category Code | 123/2023 |
| Date of Test | 22 July 2024 |
| Medium of Question | ENGLISH |
| Exam Type | OMR Examination |
| Total Questions | 100 |
1
The average power in watts delivered to Z_L = 8 − j4 Ω by an ideal current source i(t) = 4 sin(ωt + 30°) A is
Answer
C. 64 W
2
A sine wave has a peak value of 20 V. Its peak factor is :
Answer
C. 1.414
3
The input voltage to a converter is v(t) = 200 sin(100πt) V and the current is i(t) = 10 sin(100πt − 60°) + 10 sin(300πt + 45°) + 2 sin(700πt − 30°) A. The active power drawn is
Answer
D. 500 W
4
A capacitor is initially charged to V_o = 100 V with its upper plate positive. The shown circuit has a 200 V source, switch S, diode D and R = 10 Ω in series with the capacitor. The switch closes at t = 0. The current at t = 0 and final capacitor voltage are respectively
Answer
A. 10 A and 200 V
5
The shown resonant circuit has an AC source and R in series with coupled coils L₁ and L₂; C is connected across L₂. For R = 10 Ω, L₁ = L₂ = 10 mH, M = 5 mH and C = 0.03 μF, its resonant frequency is
Answer
D. 5.3 kHz
6
Find the power delivered to the 400 Ω load if n = 10. The diagram has an 8∠0° A rms current source feeding parallel branches of 10 Ω and a series 6 Ω plus ideal transformer of turns ratio 1:n, with 400 Ω on the secondary.
Answer
C. 64 W
7
Consider the following statements :
(1) The phase angle between voltage across inductor and voltage across capacitor is
180° for a series RLC circuit.
(2) The current accepted at resonance is maximum in a parallel RLC circuit.
(3) The sum of inductor and capacitor currents is maximum at resonance in a parallel
RLC circuit.
Which of the above statements are true?
Answer
D. Only (1)
089/2024 4 A
8
What will be the value of X C so that the circuit is resistive?
Answer
C. 10 Ω
9
In the figure below, the steady state current through inductor is :
Answer
C. 2 sin(2t − 15°)
10
In the RL circuit shown, the power consumed by 20 Ω resistor is given as 80 W. Then the
power factor of the circuit is :
Answer
C. 0.707
11
The magnetic flux through a coil of wire can be increased by :
Answer
A. increasing the number of turns in the coil
12
The mutual inductance between two coils depends on their :
Answer
D. coupling co-efficient
13
The magnetic field around a current carrying conductor is :
Answer
A. circular
14
An inductor is connected in series with a resistor in an ac circuit. The phase difference
between current and voltage across the resistor is :
Answer
A. 0 degree
15
Which material is commonly used for the core of an inductor or transformer due to its high
permeability?
Answer
D. Iron
16
The power factor of an inductive circuit can be improved by connecting
Answer
B. capacitor in parallel
17
The magnetic reluctance of a material is directly proportional to :
Answer
Question Cancelled
18
Which of the following is a magnetic insulator?
Answer
D. none of the above
089/2024 6 A
19
Calculate the ratio of inductance of a ring shaped coil with mean diameter 200 mm
containing 500 turns is wound on a wooden core and iron core of diameter 200 mm. The
current is 5 A and the relative permeability of iron is 600 :
Answer
B. 1 : 600
20
What is the flux density at a point 60 mm in air from a long straight conductor carrying a
current of 500 A?
Answer
C. 1.67 × 10 −3 T
21
Polarity of a DC generator can be reversed by :
Answer
C. Reversing the field current or reversing the direction of rotation
22
Hysteresis loss in a DC machine depend on :
Answer
D. All of the above
23
If the direction of power flow changes, a cumulative compound motor becomes :
Answer
D. Differentially compound generator
24
If the terminal voltage of a DC generator remains the same as the no load terminal voltage, it
is
Answer
C. Cumulatively compound generator
25
A 230 V, 100 W bulb is connected in series with the primary of a 230/115 V, 5 kVA
transformer. If the primary is energised from 230 V supply and the secondary is open, the
lamp will have :
Answer
B. Poor brightness
26
In a transformer, maximum voltage regulation occur when the power factor is :
Answer
D. Lagging
27
The relative speed between stator and rotor fluxes in a three phase induction motor while
running. (Ns-synchronous speed, Nr-rotor speed) :
Answer
D. 0
28
If the mechanical load on a three phase induction motor is increased, its power factor :
Answer
A. Increases
29
The advantage of a short pitch winding is :
Answer
A. Suppression of harmonics
30
For a constant load, the magnitude of armature current is high for :
Answer
Question Cancelled
31
The octal representation of an integer is (372)8. If this were to be treated as an eight-bit
integer in an 8085-based computer, its decimal equivalent is :
Answer
C. –6
32
___________ code is used in digital measuring devices because it reduces the likelihood of
errors.
Answer
A. Gray code
33
Which of the following properties are available in a universal shift register?
(1) Shift Left
(2) Shift Right
(3) Parallel load
(4) Serial load
Answer
B. (1), (2) and (3)
34
Assertion (A) : Master-slave flip flop is free from multiple triggering.
Reason (R) : In the master-slave configuration, slave prevents the multiple triggering
since its clock signal is inverted.
Answer
A. Both
35
The resolution of a 4-bit DAC with a range of output voltage from 0-5 V is :
Answer
A. 0.33 V
36
Which of the following input signal that can be used by slow peripherals to get extra time in
order to communicate with 8085?
Answer
D. READY
37
Which interrupt has highest priority in 8085?
Answer
A. TRAP
38
In 8085 microprocessors, which of the following statement is FALSE?
Answer
B. 8085 microprocessor has bidirectional address bus
39
In 8085 microprocessor, let the accumulator contain the value 0AH and register C contain
the value 05H. After CMP C instruction is executed :
Answer
C. Zero flag and Carry flag will be reset
40
What operation is performed during the first T state of every machine cycle in 8085?
Answer
C. Low byte address is latched into an external latch using ALE signal
41
A power system experiences a corona loss of 1 kW/km/ph at a frequency of 50 Hz. If the
frequency is increased to 100 Hz while keeping everything else constant, how much will the
corona loss change?
Answer
D. 1.667 kW/km/ph
42
For a transmission line experiencing severe power surges, what type of relay offers the most
accurate and reliable fault detection and isolation?
Answer
A. Mho relay
43
A synchronous machine has a per unit impedance of 0.4 at a specific base voltage. If we select
a new base voltage that is 2 times higher, what will the new per unit impedance of the
machine?
Answer
B. 0.1
44
The Ferranti effect describes a phenomenon in long overhead transmission lines. When is the
Ferranti effect most likely to occur?
Answer
C. When the line is lightly loaded or at no load
45
A line-to-ground fault occurs on a power system. The current in the faulted phase is
measured at 300 A. What will be the zero sequence current in this scenario?
Answer
D. 100
46
A single-line-to-ground fault occurs on a 3-phase system with an ungrounded neutral and a
line-to-neutral voltage of 11 kV. To what value will the voltage on the healthy phases most
likely to rise?
Answer
B. √3 × 11 kV
47
What is the critical factor that determines the stability of a power system under small
disturbances?
Answer
C. System inertia
48
Why does the voltage across the discs of a string of suspension insulators with identical discs
differ, even though they are connected in series?
Answer
B. shunt capacitance to ground
49
String efficiency is an important consideration for designing transmission lines. Why is it
important to have a high string efficiency?
Answer
A. It ensures a more uniform distribution of voltage stress across the discs
50
SF6 circuit breakers are widely used in high voltage applications. What is the primary reason
for this preference over other types of breakers?
Answer
C. The superior insulating and arc quenching properties
51
1
If the overall transfer function of system shown in the figure is , then what
s + 3s2 + 2s
3
would be the transfer function of G .
1 1
Answer
B. 2
s +2 s +s
1 1
52
A system has two resistors with values of 6 ohm and 10 ohm, respectively and an inductor
with a value of 2 henry. A voltage source (V ) , serving as the system’s input, connects these
components in series. Determine the transfer function of the system if the voltage across the
6 – ohm resistor is the output :
3 s
Answer
A. ——
53
The following statements represent the transient performance of two systems :
System A has a settling time of 4 seconds and a peak overshoot of 15%.
System B has a 2 second settling time and a 25% peak overshoot.
Then which of the following statements is true.
Answer
D. System A exhibits slower response and better relative stability
54
The transfer function of a system is :
s2 + 3
G= , then
s3 (2 + 3s + s2 )
Answer
B. The order of system is 5 and type of system is 3
55
The steady state error of a system to a step input is 0.2. The system is now cascaded with an
integrator. Then the steady state error to a ramp input will be :
Answer
B. 0.25
56
A negative feedback closed loop system is being applied with a voltage of 10 V. The system
has a forward gain of 5 and a feedback gain of 0.2. The output voltage and the error voltage
are :
Answer
D. 25 V, 5 V
57
The characteristic equation of a closed-loop system is s⁴ + 5s² + 3s + K = 0. The value of k that ensures stability is
Answer
Question Cancelled
58
A feedback control system's open-loop transfer function has a polar plot that intersects the real axis at −5. The system's gain margin in dB is (assume log 5 = 0.698)
Answer
D. −13.96
59
Which of the following has the advantage of converting the multiplication of gains into
addition?
Answer
A. Bode plot
60
The elements of first columns of a Routh’s table are 1, 3, –0.5, 6, 0.2. It means that :
Answer
C. Two roots are on right half of s-plane
61
The following statements refer to the conditions for successful turn on of an SCR when given
a single triggering pulse, when the SCR is connected to an RL load :
(i) SCR should be forward biased.
(ii) SCR should be reverse biased.
(iii) Gate pulse should be applied across Gate and Cathode.
(iv) Gate pulse should be applied across Gate and Anode.
(v) Gate pulse should be present for a minimum time such that the anode current reaches
the latching current within that time.
(vi) Gate pulse should be present for a minimum time such that the anode current reaches
the holding current within that time.
Choose the correct combination of statements.
Answer
D. (i), (iii) and (v)
62
A single–phase fully controlled converter feeding an RL load with back emf 150 V, with
single–phase AC source with rms voltage 230 V at 50 Hz as input. If the load is such that the
current in the load is discontinuous, what will be the voltage across the load terminals during
the period of discontinuity?
Answer
C. 150 V
63
The configuration of a three-phase half-controlled converter has :
Answer
C. 3 SCRs and 3 diodes
64
A three-phase fully controlled converter was operating with RL load and continuous load current. The firing angle α = 60°. During a repair, engineers replaced three thyristors on the bottom side of the converter bridge (T4, T6 and T2 in the usual naming convention) with diodes. What change in average output voltage will be observed with the same firing angle?
Answer
B. 1.5 times the previous output
65
Which of the following statements is correct with reference to a Voltage Source Inverter
(VSI)?
Answer
A. The DC voltage is unipolar and DC current could be bipolar
66
The output rms voltage of a single-phase bridge inverter with square wave output
requirement, can be varied with :
Answer
A. Variation of DC voltage only
67
A single-phase full-bridge voltage source inverter with dc link voltage of 100 V is modulated
using Unipolar Sinusoidal PWM. The switching frequency is 5 kHz. The load impedance at
fundamental frequency is 10 Ω. The triangular carrier used for the modulation has an
amplitude of 4 V and the reference sine wave has an amplitude of 3 V. What is the amplitude
of the fundamental component of load current?
Answer
B. 7.5 A
68
For a step-down chopper feeding an RL load with R = 2 Ω, L = 4 mH, f = 1 kHz, duty ratio = 60% and V_dc = 48 V, the DC load current is
Answer
B. 14.4 A
69
A sinusoidal signal with amplitude 20 mV is applied to the input of an inverting amplifier
based on an opamp. The feedback path resistance is 250 kΩ and the input side resistance is
10 kΩ. The slew rate of the opamp is 0.5 V/μs. What is the maximum frequency of the input
signal with the given amplitude that may be used without output distortion?
Answer
A. 106 rad/s
70
The circuit is an instrumentation-style amplifier. V_i = 0.02 V drives a non-inverting stage with 200 kΩ feedback and 20 kΩ to ground; its output and a unity-buffered copy of V_i feed an inverting summer through 10 kΩ and 5 kΩ, with 50 kΩ feedback. The output voltage V_o is
Answer
C. –1.3 V
71
The ratio of difference between measured value and true value to the true value of a value
under measurement is?
Answer
D. Relative static error
72
Which of the following is the fixed coil in an electrodynamometer type wattmeter?
Answer
A. Current coil
73
An energy meter can be best categorized as an instrument of :
Answer
D. Integrating type
74
What value is typically expected while measuring a quantity using a PMMC instrument?
Answer
A. Average value
75
The pressure coil of a wattmeter should be connected on the supply side and current coil is
connected on the load side, when?
Answer
A. Load impedance is high
76
The current under measurement is i = 2 + 4 sin(314t) A. If measured using a moving-iron instrument, what value can be shown?
Answer
D. 3.46 A
77
Which of the following instrument has the least loading effect on the circuit under
measurement?
Answer
C. Electrostatic
78
What are the two measurements that can be carried out using Lissajous figure?
Answer
C. Frequency and phase
79
The constant load current for a 230 V single phase energy meter is 10 A at unity power
factor. If the meter makes 2300 revolutions in 2 hours. What will be the meter constant?
Answer
B. 500 revolutions/kWh
80
What should be the value of shunt resistance required to extend the range of a 10A ammeter
so that it could measure 100A. Consider the internal resistance of ammeter to be 0.09 Ω?
Answer
A. 0.01 Ω
81
Which of the following statement best defines a signal?
Answer
C. Signal is a physical quantity that varies with time, space or any other
independent variables
82
Find the fundamental period of the signal X(t) = je^(j10t).
Answer
A. π/5 sec
83
Which of the following function is a periodic signal?
Answer
D. X(t) = 4cos(5πt)
84
Find the fundamental period of X(t) = 7 cos(5t + 7) + 9 sin(6t + 9).
Answer
C. 2π
85
For an energy signal which of the following is true?
Answer
B. P =0
86
The system represented by y (n ) = 5x (n ) + 3x (n − 2) + x (n + 3) is :
Answer
D. Dynamic and non-Causal
87
If a signal x(t) has energy E, the energy of signal x(2t) is:
Answer
C. E/2
88
Evaluate ∫₋∞⁺∞ e⁻ᵗ δ(2t − 2) dt.
Answer
B. 1/(2e)
89
In a sample and hold circuit the time required for conversion of analog to digital is
___________ to the duration of hold mode.
Answer
B. Less than
90
Determine the Nyquist rate for x(t) = 1 + cos(2000πt) + sin²(4000πt).
Answer
C. 16,000π
91
Calculate the illuminance on a surface 5 meters away from a lamp emitting 1500 lumens.
Answer
A. 60
92
A point source of light emits 500 lumens. What is the luminous intensity of the source?
Answer
B. 40 candela
93
If two 12V batteries each with a capacity of 150 Ah are connected in parallel, what is the
total capacity in Ah?
Answer
C. 300 Ah
94
If an LVDT has an output voltage range of ±10 V for a displacement range of ±10 mm, what
is the sensitivity of the LVDT in V/mm?
Answer
C. 1 V/mm
95
A Hall effect transducer is used to measure the strength of a magnetic field. The transducer
has a Hall coefficient of 5 × 10–5 m3/C and a thickness of 0.2 mm. If the magnetic field
strength is 0.5 T and the current through the transducer is 15 mA, what is the Hall voltage?
Answer
A. 1.875 mV
96
A Hall effect transducer is used to measure a magnetic field. If the Hall voltage generated is
2.5 mV when the magnetic field strength is 0.5 T and the current flowing through the sensor
is 10 mA, what is the sensitivity of the Hall effect transducer?
Answer
B. 0.5 mV/T
97
Which type of earthing is commonly used in homes?
Answer
C. Rod earthing
98
If a 20-meter-long copper wire has a resistance of 0.03 ohms, what is the resistance of a
60-meter-long wire of the same type and thickness?
Answer
B. 0.09 Ω
99
A rotary potentiometer is used as an angular displacement transducer. If the total resistance
of the potentiometer is 20 kΩ and the angular displacement is 90°, what is the resistance
change for this displacement, assuming a linear relationship?
Answer
A. 5 KΩ
100
How many 3.7 V, 3000 mAh lithium-ion cells are needed to create a 22.2 V battery pack with
a capacity of 6000 mAh?
Answer
C. 12 cells (6 cells in series and 2 in parallel)
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